Hi,
I think this seems to be a known use case for industrial these days with i.mx8m.
The host DSI would configure with two bridges one for DSI to LVDS (SN65DSI83) and another for DSI to HDMI Out (ADV7535). Technically we can use only one bridge at a time as host DSI support single out port. So we can have two separate device tree files for LVDS and HDMI and load them static.
But, one of the use cases is to support both of them in single dts, and - Turn On LVDS (default) - Turn Off LVDS then Turn On HDMI when cable plug-in.
The HDMI event can be detected via some HDMI-INT GPIO on-board design.
The possible solution, I'm thinking of adding LVDS on port 1, HDMI on port 2 in the DSI host node, and trying to attach the respective bridge based on HDMI-INT like repeating the bridge attachment cycle based on the HDMI-INT.
Can it be possible to do bridge attachment at runtime? something like a bridge hotplug event? or any other possible solutions?
Any suggestions?
Thanks, Jagan.
Hi,
Removed my invalid email (I will update files next week).
On 08.10.2021 13:14, Jagan Teki wrote:
Hi,
I think this seems to be a known use case for industrial these days with i.mx8m.
The host DSI would configure with two bridges one for DSI to LVDS (SN65DSI83) and another for DSI to HDMI Out (ADV7535). Technically we can use only one bridge at a time as host DSI support single out port. So we can have two separate device tree files for LVDS and HDMI and load them static.
But, one of the use cases is to support both of them in single dts, and
- Turn On LVDS (default)
- Turn Off LVDS then Turn On HDMI when cable plug-in
Are you sure it will work from hardware PoV? Do you have some demuxer? isolation of pins?
The HDMI event can be detected via some HDMI-INT GPIO on-board design.
The possible solution, I'm thinking of adding LVDS on port 1, HDMI on port 2 in the DSI host node, and trying to attach the respective bridge based on HDMI-INT like repeating the bridge attachment cycle based on the HDMI-INT.
I think more appropriate would be to share the same port, but provide two endpoints inside this port - we have two hardware sharing the same physical port.
Can it be possible to do bridge attachment at runtime? something like a bridge hotplug event? or any other possible solutions?
Any suggestions?
Practically it is possible, see exynos_dsi + panels, or exynos_dsi + some toshiba bridge - panel and bridge are dynamically 'plugged' and 'unplugged' from exynos_drm, but they do not use bridge chain for this and some other reasons. (un|re|)plugging should be performed of course when pipeline is off (connector disconnected). I am not sure about bridges added to bridge chain - you need to inspect all opses to ensure it can be done safely.
And the main issue: Daniel does not like it :)
Regards Andrzej
Thanks, Jagan.
Hello,
On Fri, Oct 08, 2021 at 03:27:43PM +0200, Andrzej Hajda wrote:
Hi,
Removed my invalid email (I will update files next week).
On 08.10.2021 13:14, Jagan Teki wrote:
Hi,
I think this seems to be a known use case for industrial these days with i.mx8m.
The host DSI would configure with two bridges one for DSI to LVDS (SN65DSI83) and another for DSI to HDMI Out (ADV7535). Technically we can use only one bridge at a time as host DSI support single out port. So we can have two separate device tree files for LVDS and HDMI and load them static.
But, one of the use cases is to support both of them in single dts, and
- Turn On LVDS (default)
- Turn Off LVDS then Turn On HDMI when cable plug-in
Are you sure it will work from hardware PoV? Do you have some demuxer? isolation of pins?
It may be in the category of "you shouldn't do this, but it actually works". I've seen the same being done with two CSI-2 camera sensors connected to the same receiver, with one of them being held in reset at all times.
The HDMI event can be detected via some HDMI-INT GPIO on-board design.
The possible solution, I'm thinking of adding LVDS on port 1, HDMI on port 2 in the DSI host node, and trying to attach the respective bridge based on HDMI-INT like repeating the bridge attachment cycle based on the HDMI-INT.
I think more appropriate would be to share the same port, but provide two endpoints inside this port - we have two hardware sharing the same physical port.
That sounds like the correct DT description to me.
Can it be possible to do bridge attachment at runtime? something like a bridge hotplug event? or any other possible solutions?
Any suggestions?
Practically it is possible, see exynos_dsi + panels, or exynos_dsi + some toshiba bridge - panel and bridge are dynamically 'plugged' and 'unplugged' from exynos_drm, but they do not use bridge chain for this and some other reasons. (un|re|)plugging should be performed of course when pipeline is off (connector disconnected). I am not sure about bridges added to bridge chain - you need to inspect all opses to ensure it can be done safely.
And the main issue: Daniel does not like it :)
Neither do I :-) Could it be handled with two DRM connectors that are mutually exclusive ?
On Fri, 8 Oct 2021 at 14:37, Laurent Pinchart laurent.pinchart@ideasonboard.com wrote:
Hello,
On Fri, Oct 08, 2021 at 03:27:43PM +0200, Andrzej Hajda wrote:
Hi,
Removed my invalid email (I will update files next week).
On 08.10.2021 13:14, Jagan Teki wrote:
Hi,
I think this seems to be a known use case for industrial these days with i.mx8m.
The host DSI would configure with two bridges one for DSI to LVDS (SN65DSI83) and another for DSI to HDMI Out (ADV7535). Technically we can use only one bridge at a time as host DSI support single out port. So we can have two separate device tree files for LVDS and HDMI and load them static.
But, one of the use cases is to support both of them in single dts, and
- Turn On LVDS (default)
- Turn Off LVDS then Turn On HDMI when cable plug-in
Are you sure it will work from hardware PoV? Do you have some demuxer? isolation of pins?
It may be in the category of "you shouldn't do this, but it actually works". I've seen the same being done with two CSI-2 camera sensors connected to the same receiver, with one of them being held in reset at all times.
Surely the correct way to do this would be with a D-PHY mux chip such as OnSemi FSA642 [1] or those from Diodes Incorporated [2]. How you'd integrate such a mux into DRM is a totally different question. With V4L2 and CSI2 it'd be relatively simple via Media Controller.
Just wiring them together isn't going to work very well for DSI reverse direction communication, but neither of the chips Jagan lists support this.
Dave
[1] https://www.onsemi.com/products/interfaces/analog-switches/fsa642 [2] https://www.diodes.com/products/connectivity-and-timing/switches-mux/protoco...
The HDMI event can be detected via some HDMI-INT GPIO on-board design.
The possible solution, I'm thinking of adding LVDS on port 1, HDMI on port 2 in the DSI host node, and trying to attach the respective bridge based on HDMI-INT like repeating the bridge attachment cycle based on the HDMI-INT.
I think more appropriate would be to share the same port, but provide two endpoints inside this port - we have two hardware sharing the same physical port.
That sounds like the correct DT description to me.
Can it be possible to do bridge attachment at runtime? something like a bridge hotplug event? or any other possible solutions?
Any suggestions?
Practically it is possible, see exynos_dsi + panels, or exynos_dsi + some toshiba bridge - panel and bridge are dynamically 'plugged' and 'unplugged' from exynos_drm, but they do not use bridge chain for this and some other reasons. (un|re|)plugging should be performed of course when pipeline is off (connector disconnected). I am not sure about bridges added to bridge chain - you need to inspect all opses to ensure it can be done safely.
And the main issue: Daniel does not like it :)
Neither do I :-) Could it be handled with two DRM connectors that are mutually exclusive ?
-- Regards,
Laurent Pinchart
Hi Dave,
On Fri, Oct 8, 2021 at 9:32 PM Dave Stevenson dave.stevenson@raspberrypi.com wrote:
On Fri, 8 Oct 2021 at 14:37, Laurent Pinchart laurent.pinchart@ideasonboard.com wrote:
Hello,
On Fri, Oct 08, 2021 at 03:27:43PM +0200, Andrzej Hajda wrote:
Hi,
Removed my invalid email (I will update files next week).
On 08.10.2021 13:14, Jagan Teki wrote:
Hi,
I think this seems to be a known use case for industrial these days with i.mx8m.
The host DSI would configure with two bridges one for DSI to LVDS (SN65DSI83) and another for DSI to HDMI Out (ADV7535). Technically we can use only one bridge at a time as host DSI support single out port. So we can have two separate device tree files for LVDS and HDMI and load them static.
But, one of the use cases is to support both of them in single dts, and
- Turn On LVDS (default)
- Turn Off LVDS then Turn On HDMI when cable plug-in
Are you sure it will work from hardware PoV? Do you have some demuxer? isolation of pins?
It may be in the category of "you shouldn't do this, but it actually works". I've seen the same being done with two CSI-2 camera sensors connected to the same receiver, with one of them being held in reset at all times.
Surely the correct way to do this would be with a D-PHY mux chip such as OnSemi FSA642 [1] or those from Diodes Incorporated [2]. How you'd integrate such a mux into DRM is a totally different question. With V4L2 and CSI2 it'd be relatively simple via Media Controller.
Just wiring them together isn't going to work very well for DSI reverse direction communication, but neither of the chips Jagan lists support this.
Sorry to mention it before, we have two 2:1 MIPI D-PHY Switch [1] on the design which take 2 data-lanes and clock from Host and produce 4 data-lane and 1 clock to connect to ADV7535 and SN65DSI84 bridges. The switch has OE, SEL pins to select the desired to MUXed lanes/clock routing to an appropriate bridge.
I think supporting the switch in the pipeline or logic that handle the bridge switching might help.
[1] https://www.diodes.com/assets/Datasheets/PI3WVR626.pdf
Jagan.
On Mon, Oct 11, 2021 at 12:51 AM Jagan Teki jagan@amarulasolutions.com wrote:
Hi Dave,
On Fri, Oct 8, 2021 at 9:32 PM Dave Stevenson dave.stevenson@raspberrypi.com wrote:
On Fri, 8 Oct 2021 at 14:37, Laurent Pinchart laurent.pinchart@ideasonboard.com wrote:
Hello,
On Fri, Oct 08, 2021 at 03:27:43PM +0200, Andrzej Hajda wrote:
Hi,
Removed my invalid email (I will update files next week).
On 08.10.2021 13:14, Jagan Teki wrote:
Hi,
I think this seems to be a known use case for industrial these days with i.mx8m.
The host DSI would configure with two bridges one for DSI to LVDS (SN65DSI83) and another for DSI to HDMI Out (ADV7535). Technically we can use only one bridge at a time as host DSI support single out port. So we can have two separate device tree files for LVDS and HDMI and load them static.
But, one of the use cases is to support both of them in single dts, and
- Turn On LVDS (default)
- Turn Off LVDS then Turn On HDMI when cable plug-in
Are you sure it will work from hardware PoV? Do you have some demuxer? isolation of pins?
It may be in the category of "you shouldn't do this, but it actually works". I've seen the same being done with two CSI-2 camera sensors connected to the same receiver, with one of them being held in reset at all times.
Surely the correct way to do this would be with a D-PHY mux chip such as OnSemi FSA642 [1] or those from Diodes Incorporated [2]. How you'd integrate such a mux into DRM is a totally different question. With V4L2 and CSI2 it'd be relatively simple via Media Controller.
Just wiring them together isn't going to work very well for DSI reverse direction communication, but neither of the chips Jagan lists support this.
Sorry to mention it before, we have two 2:1 MIPI D-PHY Switch [1] on the design which take 2 data-lanes and clock from Host and produce 4 data-lane and 1 clock to connect to ADV7535 and SN65DSI84 bridges. The switch has OE, SEL pins to select the desired to MUXed lanes/clock routing to an appropriate bridge.
I think supporting the switch in the pipeline or logic that handle the bridge switching might help.
MIPI Switch (PI3WVR626) has OE, SEL logic to select respective data and clock lanes which are routed to bridge/panel. I think, these OE and SEL logic can be part of pinmux so we can configure them on respective bridge/panel nodes pinctrl (atleast on imx8m) instead of handling them as separate nodes.
Jagan.
Hi Laurent,
On Fri, Oct 8, 2021 at 7:07 PM Laurent Pinchart laurent.pinchart@ideasonboard.com wrote:
Hello,
On Fri, Oct 08, 2021 at 03:27:43PM +0200, Andrzej Hajda wrote:
Hi,
Removed my invalid email (I will update files next week).
On 08.10.2021 13:14, Jagan Teki wrote:
Hi,
I think this seems to be a known use case for industrial these days with i.mx8m.
The host DSI would configure with two bridges one for DSI to LVDS (SN65DSI83) and another for DSI to HDMI Out (ADV7535). Technically we can use only one bridge at a time as host DSI support single out port. So we can have two separate device tree files for LVDS and HDMI and load them static.
But, one of the use cases is to support both of them in single dts, and
- Turn On LVDS (default)
- Turn Off LVDS then Turn On HDMI when cable plug-in
Are you sure it will work from hardware PoV? Do you have some demuxer? isolation of pins?
It may be in the category of "you shouldn't do this, but it actually works". I've seen the same being done with two CSI-2 camera sensors connected to the same receiver, with one of them being held in reset at all times.
Yes. Here the design has 2 MIPI D-PHY switches. Each switch take 2 input data lanes and 1 clock lane from SoC and produces 4 data lanes and 2 clock lanes and from switch output 2 lanes and 1 clock are inputting to HDMI bridge and other 2 lanes and 1 clock is inputting to LVDS. So 1st pair of 1st switch and 1st pair of 2nd switch goes to HDMI and 2nd pair of 1st switch and 2nd pair of 2nd switch does to LVDS.
However, routing of these lanes are controlled by SEL, OE GPIO pins. So at a time we can access only single bridge.
The HDMI event can be detected via some HDMI-INT GPIO on-board design.
The possible solution, I'm thinking of adding LVDS on port 1, HDMI on port 2 in the DSI host node, and trying to attach the respective bridge based on HDMI-INT like repeating the bridge attachment cycle based on the HDMI-INT.
I think more appropriate would be to share the same port, but provide two endpoints inside this port - we have two hardware sharing the same physical port.
That sounds like the correct DT description to me.
Can it be possible to do bridge attachment at runtime? something like a bridge hotplug event? or any other possible solutions?
Any suggestions?
Practically it is possible, see exynos_dsi + panels, or exynos_dsi + some toshiba bridge - panel and bridge are dynamically 'plugged' and 'unplugged' from exynos_drm, but they do not use bridge chain for this and some other reasons. (un|re|)plugging should be performed of course when pipeline is off (connector disconnected). I am not sure about bridges added to bridge chain - you need to inspect all opses to ensure it can be done safely.
And the main issue: Daniel does not like it :)
Neither do I :-) Could it be handled with two DRM connectors that are mutually exclusive ?
How about adding lvds-connector, hdmi-connector on the pipeline and select them based on the switch SEL GPIO? does it make sense to do this implementation via display-connector.c
Thanks, Jagan.
or a Hi All,
On Thu, Oct 14, 2021 at 6:45 PM Jagan Teki jagan@amarulasolutions.com wrote:
Hi Laurent,
On Fri, Oct 8, 2021 at 7:07 PM Laurent Pinchart laurent.pinchart@ideasonboard.com wrote:
Hello,
On Fri, Oct 08, 2021 at 03:27:43PM +0200, Andrzej Hajda wrote:
Hi,
Removed my invalid email (I will update files next week).
On 08.10.2021 13:14, Jagan Teki wrote:
Hi,
I think this seems to be a known use case for industrial these days with i.mx8m.
The host DSI would configure with two bridges one for DSI to LVDS (SN65DSI83) and another for DSI to HDMI Out (ADV7535). Technically we can use only one bridge at a time as host DSI support single out port. So we can have two separate device tree files for LVDS and HDMI and load them static.
But, one of the use cases is to support both of them in single dts, and
- Turn On LVDS (default)
- Turn Off LVDS then Turn On HDMI when cable plug-in
Are you sure it will work from hardware PoV? Do you have some demuxer? isolation of pins?
It may be in the category of "you shouldn't do this, but it actually works". I've seen the same being done with two CSI-2 camera sensors connected to the same receiver, with one of them being held in reset at all times.
Yes. Here the design has 2 MIPI D-PHY switches. Each switch take 2 input data lanes and 1 clock lane from SoC and produces 4 data lanes and 2 clock lanes and from switch output 2 lanes and 1 clock are inputting to HDMI bridge and other 2 lanes and 1 clock is inputting to LVDS. So 1st pair of 1st switch and 1st pair of 2nd switch goes to HDMI and 2nd pair of 1st switch and 2nd pair of 2nd switch does to LVDS.
However, routing of these lanes are controlled by SEL, OE GPIO pins. So at a time we can access only single bridge.
The HDMI event can be detected via some HDMI-INT GPIO on-board design.
The possible solution, I'm thinking of adding LVDS on port 1, HDMI on port 2 in the DSI host node, and trying to attach the respective bridge based on HDMI-INT like repeating the bridge attachment cycle based on the HDMI-INT.
I think more appropriate would be to share the same port, but provide two endpoints inside this port - we have two hardware sharing the same physical port.
That sounds like the correct DT description to me.
Can it be possible to do bridge attachment at runtime? something like a bridge hotplug event? or any other possible solutions?
Any suggestions?
Practically it is possible, see exynos_dsi + panels, or exynos_dsi + some toshiba bridge - panel and bridge are dynamically 'plugged' and 'unplugged' from exynos_drm, but they do not use bridge chain for this and some other reasons. (un|re|)plugging should be performed of course when pipeline is off (connector disconnected). I am not sure about bridges added to bridge chain - you need to inspect all opses to ensure it can be done safely.
And the main issue: Daniel does not like it :)
Neither do I :-) Could it be handled with two DRM connectors that are mutually exclusive ?
How about adding lvds-connector, hdmi-connector on the pipeline and select them based on the switch SEL GPIO? does it make sense to do this implementation via display-connector.c
I have somehow managed to make runtime switching possible between LVDS and HDMI with the help of DRM bridges.
| => ADV7535 => HDMI-A Connector DSI Host => display-switch => | |=> SN65DSI83 => Panel-Simple
display-switch here is a bridge driver that can switch or attach the downstream bridge flow based on HDMI HPD here. One potential problem is that when we switch from LVDS to HDMI Out the HDMI Out is displayed with the resolution that LVDS has and it is unable to display higher HDMI resolutions even though it supports it. Does anyone aware of changing the resolution at runtime, please let me know?
Technically, the display-switch hardware does available in various forms 1. MIPI Switch PI3WVR626 2. Conventional Mux Switch 3. Converter bridge DSI to LVDS/HDMI (from Lontium).
Overall I believe this can be a potential possible feature and good to support on Mainline as the hardware is intended to design for it.
Any thoughts on this please let me know?
Thanks, Jagan.
On Wed, Mar 9, 2022 at 1:11 PM Jagan Teki jagan@amarulasolutions.com wrote:
or a Hi All,
On Thu, Oct 14, 2021 at 6:45 PM Jagan Teki jagan@amarulasolutions.com wrote:
Hi Laurent,
On Fri, Oct 8, 2021 at 7:07 PM Laurent Pinchart laurent.pinchart@ideasonboard.com wrote:
Hello,
On Fri, Oct 08, 2021 at 03:27:43PM +0200, Andrzej Hajda wrote:
Hi,
Removed my invalid email (I will update files next week).
On 08.10.2021 13:14, Jagan Teki wrote:
Hi,
I think this seems to be a known use case for industrial these days with i.mx8m.
The host DSI would configure with two bridges one for DSI to LVDS (SN65DSI83) and another for DSI to HDMI Out (ADV7535). Technically we can use only one bridge at a time as host DSI support single out port. So we can have two separate device tree files for LVDS and HDMI and load them static.
But, one of the use cases is to support both of them in single dts, and
- Turn On LVDS (default)
- Turn Off LVDS then Turn On HDMI when cable plug-in
Are you sure it will work from hardware PoV? Do you have some demuxer? isolation of pins?
It may be in the category of "you shouldn't do this, but it actually works". I've seen the same being done with two CSI-2 camera sensors connected to the same receiver, with one of them being held in reset at all times.
Yes. Here the design has 2 MIPI D-PHY switches. Each switch take 2 input data lanes and 1 clock lane from SoC and produces 4 data lanes and 2 clock lanes and from switch output 2 lanes and 1 clock are inputting to HDMI bridge and other 2 lanes and 1 clock is inputting to LVDS. So 1st pair of 1st switch and 1st pair of 2nd switch goes to HDMI and 2nd pair of 1st switch and 2nd pair of 2nd switch does to LVDS.
However, routing of these lanes are controlled by SEL, OE GPIO pins. So at a time we can access only single bridge.
The HDMI event can be detected via some HDMI-INT GPIO on-board design.
The possible solution, I'm thinking of adding LVDS on port 1, HDMI on port 2 in the DSI host node, and trying to attach the respective bridge based on HDMI-INT like repeating the bridge attachment cycle based on the HDMI-INT.
I think more appropriate would be to share the same port, but provide two endpoints inside this port - we have two hardware sharing the same physical port.
That sounds like the correct DT description to me.
Can it be possible to do bridge attachment at runtime? something like a bridge hotplug event? or any other possible solutions?
Any suggestions?
Practically it is possible, see exynos_dsi + panels, or exynos_dsi + some toshiba bridge - panel and bridge are dynamically 'plugged' and 'unplugged' from exynos_drm, but they do not use bridge chain for this and some other reasons. (un|re|)plugging should be performed of course when pipeline is off (connector disconnected). I am not sure about bridges added to bridge chain - you need to inspect all opses to ensure it can be done safely.
And the main issue: Daniel does not like it :)
Neither do I :-) Could it be handled with two DRM connectors that are mutually exclusive ?
How about adding lvds-connector, hdmi-connector on the pipeline and select them based on the switch SEL GPIO? does it make sense to do this implementation via display-connector.c
I have somehow managed to make runtime switching possible between LVDS and HDMI with the help of DRM bridges.
| => ADV7535 =>HDMI-A Connector DSI Host => display-switch => | |=> SN65DSI83 => Panel-Simple
display-switch here is a bridge driver that can switch or attach the downstream bridge flow based on HDMI HPD here. One potential problem is that when we switch from LVDS to HDMI Out the HDMI Out is displayed with the resolution that LVDS has and it is unable to display higher HDMI resolutions even though it supports it. Does anyone aware of changing the resolution at runtime, please let me know?
Technically, the display-switch hardware does available in various forms
- MIPI Switch PI3WVR626
- Conventional Mux Switch
- Converter bridge DSI to LVDS/HDMI (from Lontium).
Overall I believe this can be a potential possible feature and good to support on Mainline as the hardware is intended to design for it.
Any thoughts on this please let me know?
I wonder if it would be possible to trigger a hot plug event similar to what is done when an HDMI cable is inserted/disconnected.
If one switches, force a disconnect event, then triggle the connection event to force the video system to rescan/attach. I am not sure how to go about implementing such a thing, but that's my first thought
adam
Thanks, Jagan.
On Wed, Mar 09, 2022 at 06:45:10PM -0600, Adam Ford wrote:
On Wed, Mar 9, 2022 at 1:11 PM Jagan Teki jagan@amarulasolutions.com wrote:
or a Hi All,
On Thu, Oct 14, 2021 at 6:45 PM Jagan Teki jagan@amarulasolutions.com wrote:
Hi Laurent,
On Fri, Oct 8, 2021 at 7:07 PM Laurent Pinchart laurent.pinchart@ideasonboard.com wrote:
Hello,
On Fri, Oct 08, 2021 at 03:27:43PM +0200, Andrzej Hajda wrote:
Hi,
Removed my invalid email (I will update files next week).
On 08.10.2021 13:14, Jagan Teki wrote:
Hi,
I think this seems to be a known use case for industrial these days with i.mx8m.
The host DSI would configure with two bridges one for DSI to LVDS (SN65DSI83) and another for DSI to HDMI Out (ADV7535). Technically we can use only one bridge at a time as host DSI support single out port. So we can have two separate device tree files for LVDS and HDMI and load them static.
But, one of the use cases is to support both of them in single dts, and
- Turn On LVDS (default)
- Turn Off LVDS then Turn On HDMI when cable plug-in
Are you sure it will work from hardware PoV? Do you have some demuxer? isolation of pins?
It may be in the category of "you shouldn't do this, but it actually works". I've seen the same being done with two CSI-2 camera sensors connected to the same receiver, with one of them being held in reset at all times.
Yes. Here the design has 2 MIPI D-PHY switches. Each switch take 2 input data lanes and 1 clock lane from SoC and produces 4 data lanes and 2 clock lanes and from switch output 2 lanes and 1 clock are inputting to HDMI bridge and other 2 lanes and 1 clock is inputting to LVDS. So 1st pair of 1st switch and 1st pair of 2nd switch goes to HDMI and 2nd pair of 1st switch and 2nd pair of 2nd switch does to LVDS.
However, routing of these lanes are controlled by SEL, OE GPIO pins. So at a time we can access only single bridge.
The HDMI event can be detected via some HDMI-INT GPIO on-board design.
The possible solution, I'm thinking of adding LVDS on port 1, HDMI on port 2 in the DSI host node, and trying to attach the respective bridge based on HDMI-INT like repeating the bridge attachment cycle based on the HDMI-INT.
I think more appropriate would be to share the same port, but provide two endpoints inside this port - we have two hardware sharing the same physical port.
That sounds like the correct DT description to me.
Can it be possible to do bridge attachment at runtime? something like a bridge hotplug event? or any other possible solutions?
Any suggestions?
Practically it is possible, see exynos_dsi + panels, or exynos_dsi + some toshiba bridge - panel and bridge are dynamically 'plugged' and 'unplugged' from exynos_drm, but they do not use bridge chain for this and some other reasons. (un|re|)plugging should be performed of course when pipeline is off (connector disconnected). I am not sure about bridges added to bridge chain - you need to inspect all opses to ensure it can be done safely.
And the main issue: Daniel does not like it :)
Neither do I :-) Could it be handled with two DRM connectors that are mutually exclusive ?
How about adding lvds-connector, hdmi-connector on the pipeline and select them based on the switch SEL GPIO? does it make sense to do this implementation via display-connector.c
I have somehow managed to make runtime switching possible between LVDS and HDMI with the help of DRM bridges.
| => ADV7535 =>HDMI-A Connector DSI Host => display-switch => | |=> SN65DSI83 => Panel-Simple
display-switch here is a bridge driver that can switch or attach the downstream bridge flow based on HDMI HPD here. One potential problem is that when we switch from LVDS to HDMI Out the HDMI Out is displayed with the resolution that LVDS has and it is unable to display higher HDMI resolutions even though it supports it. Does anyone aware of changing the resolution at runtime, please let me know?
Technically, the display-switch hardware does available in various forms
- MIPI Switch PI3WVR626
- Conventional Mux Switch
- Converter bridge DSI to LVDS/HDMI (from Lontium).
Overall I believe this can be a potential possible feature and good to support on Mainline as the hardware is intended to design for it.
Any thoughts on this please let me know?
I wonder if it would be possible to trigger a hot plug event similar to what is done when an HDMI cable is inserted/disconnected.
If one switches, force a disconnect event, then triggle the connection event to force the video system to rescan/attach. I am not sure how to go about implementing such a thing, but that's my first thought
Nothing prevents the DRM Master to just ignore the hotplug event though :) Kodi does that for example.
I think we could simply create two connectors, one for LVDS, one for HDMI, with atomic_check making sure only one of them is enabled at the same time?
The one thing that would make it difficult is that we're changing the bridge list to a tree. For example, in such a case, what should drm_bridge_get_next_bridge return? This will obviously depend on the state, but it's used in context were we don't have a state (such as drm_bridge_connector_init).
Maxime
On Thu, Mar 10, 2022 at 4:05 PM Maxime Ripard maxime@cerno.tech wrote:
On Wed, Mar 09, 2022 at 06:45:10PM -0600, Adam Ford wrote:
On Wed, Mar 9, 2022 at 1:11 PM Jagan Teki jagan@amarulasolutions.com wrote:
or a Hi All,
On Thu, Oct 14, 2021 at 6:45 PM Jagan Teki jagan@amarulasolutions.com wrote:
Hi Laurent,
On Fri, Oct 8, 2021 at 7:07 PM Laurent Pinchart laurent.pinchart@ideasonboard.com wrote:
Hello,
On Fri, Oct 08, 2021 at 03:27:43PM +0200, Andrzej Hajda wrote:
Hi,
Removed my invalid email (I will update files next week).
On 08.10.2021 13:14, Jagan Teki wrote: > Hi, > > I think this seems to be a known use case for industrial these days with i.mx8m. > > The host DSI would configure with two bridges one for DSI to LVDS > (SN65DSI83) and another for DSI to HDMI Out (ADV7535). Technically we > can use only one bridge at a time as host DSI support single out port. > So we can have two separate device tree files for LVDS and HDMI and > load them static. > > But, one of the use cases is to support both of them in single dts, and > - Turn On LVDS (default) > - Turn Off LVDS then Turn On HDMI when cable plug-in
Are you sure it will work from hardware PoV? Do you have some demuxer? isolation of pins?
It may be in the category of "you shouldn't do this, but it actually works". I've seen the same being done with two CSI-2 camera sensors connected to the same receiver, with one of them being held in reset at all times.
Yes. Here the design has 2 MIPI D-PHY switches. Each switch take 2 input data lanes and 1 clock lane from SoC and produces 4 data lanes and 2 clock lanes and from switch output 2 lanes and 1 clock are inputting to HDMI bridge and other 2 lanes and 1 clock is inputting to LVDS. So 1st pair of 1st switch and 1st pair of 2nd switch goes to HDMI and 2nd pair of 1st switch and 2nd pair of 2nd switch does to LVDS.
However, routing of these lanes are controlled by SEL, OE GPIO pins. So at a time we can access only single bridge.
> The HDMI event can be detected via some HDMI-INT GPIO on-board design. > > The possible solution, I'm thinking of adding LVDS on port 1, HDMI on > port 2 in the DSI host node, and trying to attach the respective > bridge based on HDMI-INT like repeating the bridge attachment cycle > based on the HDMI-INT.
I think more appropriate would be to share the same port, but provide two endpoints inside this port - we have two hardware sharing the same physical port.
That sounds like the correct DT description to me.
> Can it be possible to do bridge attachment at runtime? something like > a bridge hotplug event? or any other possible solutions? > > Any suggestions?
Practically it is possible, see exynos_dsi + panels, or exynos_dsi + some toshiba bridge - panel and bridge are dynamically 'plugged' and 'unplugged' from exynos_drm, but they do not use bridge chain for this and some other reasons. (un|re|)plugging should be performed of course when pipeline is off (connector disconnected). I am not sure about bridges added to bridge chain - you need to inspect all opses to ensure it can be done safely.
And the main issue: Daniel does not like it :)
Neither do I :-) Could it be handled with two DRM connectors that are mutually exclusive ?
How about adding lvds-connector, hdmi-connector on the pipeline and select them based on the switch SEL GPIO? does it make sense to do this implementation via display-connector.c
I have somehow managed to make runtime switching possible between LVDS and HDMI with the help of DRM bridges.
| => ADV7535 =>HDMI-A Connector DSI Host => display-switch => | |=> SN65DSI83 => Panel-Simple
display-switch here is a bridge driver that can switch or attach the downstream bridge flow based on HDMI HPD here. One potential problem is that when we switch from LVDS to HDMI Out the HDMI Out is displayed with the resolution that LVDS has and it is unable to display higher HDMI resolutions even though it supports it. Does anyone aware of changing the resolution at runtime, please let me know?
Technically, the display-switch hardware does available in various forms
- MIPI Switch PI3WVR626
- Conventional Mux Switch
- Converter bridge DSI to LVDS/HDMI (from Lontium).
Overall I believe this can be a potential possible feature and good to support on Mainline as the hardware is intended to design for it.
Any thoughts on this please let me know?
I wonder if it would be possible to trigger a hot plug event similar to what is done when an HDMI cable is inserted/disconnected.
If one switches, force a disconnect event, then triggle the connection event to force the video system to rescan/attach. I am not sure how to go about implementing such a thing, but that's my first thought
Nothing prevents the DRM Master to just ignore the hotplug event though :) Kodi does that for example.
Does it mean the DRM master unlocks the kodi if we switch the display? In my use-case QT is holding the DRM master so drm_master_internal_acquire returns 0 in drm_fb_helper_hotplug_event so it indeed not able to switch. But for non-qt and normal DRM console applications I can see drm_fb_helper_hotplug_event return properly in order to do the proper switching.
I think we could simply create two connectors, one for LVDS, one for HDMI, with atomic_check making sure only one of them is enabled at the same time?
How can we create two connectors at the same time? You mean try to attach LVDS and HDMI bridge one after another in display-switch attach. does it create two different bridge lists?
sndsi83 => panel-simple mxsfb => nwl-dsi => display-switch => adv7511 => display-connector
Thanks, Jagan.
On Tue, Mar 29, 2022 at 07:39:21PM +0530, Jagan Teki wrote:
On Thu, Mar 10, 2022 at 4:05 PM Maxime Ripard maxime@cerno.tech wrote:
On Wed, Mar 09, 2022 at 06:45:10PM -0600, Adam Ford wrote:
On Wed, Mar 9, 2022 at 1:11 PM Jagan Teki jagan@amarulasolutions.com wrote:
or a Hi All,
On Thu, Oct 14, 2021 at 6:45 PM Jagan Teki jagan@amarulasolutions.com wrote:
Hi Laurent,
On Fri, Oct 8, 2021 at 7:07 PM Laurent Pinchart laurent.pinchart@ideasonboard.com wrote:
Hello,
On Fri, Oct 08, 2021 at 03:27:43PM +0200, Andrzej Hajda wrote: > Hi, > > Removed my invalid email (I will update files next week). > > On 08.10.2021 13:14, Jagan Teki wrote: > > Hi, > > > > I think this seems to be a known use case for industrial these days with i.mx8m. > > > > The host DSI would configure with two bridges one for DSI to LVDS > > (SN65DSI83) and another for DSI to HDMI Out (ADV7535). Technically we > > can use only one bridge at a time as host DSI support single out port. > > So we can have two separate device tree files for LVDS and HDMI and > > load them static. > > > > But, one of the use cases is to support both of them in single dts, and > > - Turn On LVDS (default) > > - Turn Off LVDS then Turn On HDMI when cable plug-in > > Are you sure it will work from hardware PoV? Do you have some demuxer? > isolation of pins?
It may be in the category of "you shouldn't do this, but it actually works". I've seen the same being done with two CSI-2 camera sensors connected to the same receiver, with one of them being held in reset at all times.
Yes. Here the design has 2 MIPI D-PHY switches. Each switch take 2 input data lanes and 1 clock lane from SoC and produces 4 data lanes and 2 clock lanes and from switch output 2 lanes and 1 clock are inputting to HDMI bridge and other 2 lanes and 1 clock is inputting to LVDS. So 1st pair of 1st switch and 1st pair of 2nd switch goes to HDMI and 2nd pair of 1st switch and 2nd pair of 2nd switch does to LVDS.
However, routing of these lanes are controlled by SEL, OE GPIO pins. So at a time we can access only single bridge.
> > The HDMI event can be detected via some HDMI-INT GPIO on-board design. > > > > The possible solution, I'm thinking of adding LVDS on port 1, HDMI on > > port 2 in the DSI host node, and trying to attach the respective > > bridge based on HDMI-INT like repeating the bridge attachment cycle > > based on the HDMI-INT. > > I think more appropriate would be to share the same port, but provide > two endpoints inside this port - we have two hardware sharing the same > physical port.
That sounds like the correct DT description to me.
> > Can it be possible to do bridge attachment at runtime? something like > > a bridge hotplug event? or any other possible solutions? > > > > Any suggestions? > > Practically it is possible, see exynos_dsi + panels, or exynos_dsi + > some toshiba bridge - panel and bridge are dynamically 'plugged' and > 'unplugged' from exynos_drm, but they do not use bridge chain for this > and some other reasons. (un|re|)plugging should be performed of course > when pipeline is off (connector disconnected). I am not sure about > bridges added to bridge chain - you need to inspect all opses to ensure > it can be done safely. > > And the main issue: Daniel does not like it :)
Neither do I :-) Could it be handled with two DRM connectors that are mutually exclusive ?
How about adding lvds-connector, hdmi-connector on the pipeline and select them based on the switch SEL GPIO? does it make sense to do this implementation via display-connector.c
I have somehow managed to make runtime switching possible between LVDS and HDMI with the help of DRM bridges.
| => ADV7535 =>HDMI-A Connector DSI Host => display-switch => | |=> SN65DSI83 => Panel-Simple
display-switch here is a bridge driver that can switch or attach the downstream bridge flow based on HDMI HPD here. One potential problem is that when we switch from LVDS to HDMI Out the HDMI Out is displayed with the resolution that LVDS has and it is unable to display higher HDMI resolutions even though it supports it. Does anyone aware of changing the resolution at runtime, please let me know?
Technically, the display-switch hardware does available in various forms
- MIPI Switch PI3WVR626
- Conventional Mux Switch
- Converter bridge DSI to LVDS/HDMI (from Lontium).
Overall I believe this can be a potential possible feature and good to support on Mainline as the hardware is intended to design for it.
Any thoughts on this please let me know?
I wonder if it would be possible to trigger a hot plug event similar to what is done when an HDMI cable is inserted/disconnected.
If one switches, force a disconnect event, then triggle the connection event to force the video system to rescan/attach. I am not sure how to go about implementing such a thing, but that's my first thought
Nothing prevents the DRM Master to just ignore the hotplug event though :) Kodi does that for example.
Does it mean the DRM master unlocks the kodi if we switch the display?
What do you mean by "the DRM master unlocks the Kodi"? Kodi is the DRM master in that case.
In my use-case QT is holding the DRM master so drm_master_internal_acquire returns 0 in drm_fb_helper_hotplug_event so it indeed not able to switch. But for non-qt and normal DRM console applications I can see drm_fb_helper_hotplug_event return properly in order to do the proper switching.
I don't see what QT has to do with it, but like I said, nothing requires the DRM master to just ignore that hotplug event. So whatever you do, you can't rely on the master reacting to the hotplug event.
I think we could simply create two connectors, one for LVDS, one for HDMI, with atomic_check making sure only one of them is enabled at the same time?
How can we create two connectors at the same time? You mean try to attach LVDS and HDMI bridge one after another in display-switch attach. does it create two different bridge lists?
Not two lists, but the bridge list would become a tree yes
Maxime
On Wed, Mar 30, 2022 at 2:20 PM Maxime Ripard maxime@cerno.tech wrote:
On Tue, Mar 29, 2022 at 07:39:21PM +0530, Jagan Teki wrote:
On Thu, Mar 10, 2022 at 4:05 PM Maxime Ripard maxime@cerno.tech wrote:
On Wed, Mar 09, 2022 at 06:45:10PM -0600, Adam Ford wrote:
On Wed, Mar 9, 2022 at 1:11 PM Jagan Teki jagan@amarulasolutions.com wrote:
or a Hi All,
On Thu, Oct 14, 2021 at 6:45 PM Jagan Teki jagan@amarulasolutions.com wrote:
Hi Laurent,
On Fri, Oct 8, 2021 at 7:07 PM Laurent Pinchart laurent.pinchart@ideasonboard.com wrote: > > Hello, > > On Fri, Oct 08, 2021 at 03:27:43PM +0200, Andrzej Hajda wrote: > > Hi, > > > > Removed my invalid email (I will update files next week). > > > > On 08.10.2021 13:14, Jagan Teki wrote: > > > Hi, > > > > > > I think this seems to be a known use case for industrial these days with i.mx8m. > > > > > > The host DSI would configure with two bridges one for DSI to LVDS > > > (SN65DSI83) and another for DSI to HDMI Out (ADV7535). Technically we > > > can use only one bridge at a time as host DSI support single out port. > > > So we can have two separate device tree files for LVDS and HDMI and > > > load them static. > > > > > > But, one of the use cases is to support both of them in single dts, and > > > - Turn On LVDS (default) > > > - Turn Off LVDS then Turn On HDMI when cable plug-in > > > > Are you sure it will work from hardware PoV? Do you have some demuxer? > > isolation of pins? > > It may be in the category of "you shouldn't do this, but it actually > works". I've seen the same being done with two CSI-2 camera sensors > connected to the same receiver, with one of them being held in reset at > all times.
Yes. Here the design has 2 MIPI D-PHY switches. Each switch take 2 input data lanes and 1 clock lane from SoC and produces 4 data lanes and 2 clock lanes and from switch output 2 lanes and 1 clock are inputting to HDMI bridge and other 2 lanes and 1 clock is inputting to LVDS. So 1st pair of 1st switch and 1st pair of 2nd switch goes to HDMI and 2nd pair of 1st switch and 2nd pair of 2nd switch does to LVDS.
However, routing of these lanes are controlled by SEL, OE GPIO pins. So at a time we can access only single bridge.
> > > > The HDMI event can be detected via some HDMI-INT GPIO on-board design. > > > > > > The possible solution, I'm thinking of adding LVDS on port 1, HDMI on > > > port 2 in the DSI host node, and trying to attach the respective > > > bridge based on HDMI-INT like repeating the bridge attachment cycle > > > based on the HDMI-INT. > > > > I think more appropriate would be to share the same port, but provide > > two endpoints inside this port - we have two hardware sharing the same > > physical port. > > That sounds like the correct DT description to me. > > > > Can it be possible to do bridge attachment at runtime? something like > > > a bridge hotplug event? or any other possible solutions? > > > > > > Any suggestions? > > > > Practically it is possible, see exynos_dsi + panels, or exynos_dsi + > > some toshiba bridge - panel and bridge are dynamically 'plugged' and > > 'unplugged' from exynos_drm, but they do not use bridge chain for this > > and some other reasons. (un|re|)plugging should be performed of course > > when pipeline is off (connector disconnected). I am not sure about > > bridges added to bridge chain - you need to inspect all opses to ensure > > it can be done safely. > > > > And the main issue: Daniel does not like it :) > > Neither do I :-) Could it be handled with two DRM connectors that are > mutually exclusive ?
How about adding lvds-connector, hdmi-connector on the pipeline and select them based on the switch SEL GPIO? does it make sense to do this implementation via display-connector.c
I have somehow managed to make runtime switching possible between LVDS and HDMI with the help of DRM bridges.
| => ADV7535 =>HDMI-A Connector DSI Host => display-switch => | |=> SN65DSI83 => Panel-Simple
display-switch here is a bridge driver that can switch or attach the downstream bridge flow based on HDMI HPD here. One potential problem is that when we switch from LVDS to HDMI Out the HDMI Out is displayed with the resolution that LVDS has and it is unable to display higher HDMI resolutions even though it supports it. Does anyone aware of changing the resolution at runtime, please let me know?
Technically, the display-switch hardware does available in various forms
- MIPI Switch PI3WVR626
- Conventional Mux Switch
- Converter bridge DSI to LVDS/HDMI (from Lontium).
Overall I believe this can be a potential possible feature and good to support on Mainline as the hardware is intended to design for it.
Any thoughts on this please let me know?
I wonder if it would be possible to trigger a hot plug event similar to what is done when an HDMI cable is inserted/disconnected.
If one switches, force a disconnect event, then triggle the connection event to force the video system to rescan/attach. I am not sure how to go about implementing such a thing, but that's my first thought
Nothing prevents the DRM Master to just ignore the hotplug event though :) Kodi does that for example.
Does it mean the DRM master unlocks the kodi if we switch the display?
What do you mean by "the DRM master unlocks the Kodi"? Kodi is the DRM master in that case.
The QT apps that I'm running seem to hold the master (drm_master_internal_acquire returns 0) so, hotplug event is not happing. Does Kodi unlock the master like drm_master_internal_acquire returns 1 so that hotplug event happing?
In my use-case QT is holding the DRM master so drm_master_internal_acquire returns 0 in drm_fb_helper_hotplug_event so it indeed not able to switch. But for non-qt and normal DRM console applications I can see drm_fb_helper_hotplug_event return properly in order to do the proper switching.
I don't see what QT has to do with it, but like I said, nothing requires the DRM master to just ignore that hotplug event. So whatever you do, you can't rely on the master reacting to the hotplug event.
This is what I thought, but with
QT app, I can see drm_master_internal_acquire returns 0 - so drm_fb_helper_hotplug_event returns early, so hotplug is breaking.
non-QT (console) I can see drm_master_internal_acquire returns 1 - so drm_fb_helper_hotplug_event done smoothly and switched to another display.
Do drm applications (like QT) have any control over DRM master acquisition via some IOCTL or any other mechanism from userspace? if yes, maybe my QT apps are doing that.
I think we could simply create two connectors, one for LVDS, one for HDMI, with atomic_check making sure only one of them is enabled at the same time?
How can we create two connectors at the same time? You mean try to attach LVDS and HDMI bridge one after another in display-switch attach. does it create two different bridge lists?
Not two lists, but the bridge list would become a tree yes
Okay. Just to clarify. The connectors are going to create at the end of the bridge list (in my case - panel-bridge for LVDS and adv7511 for HDMI) and connectors will create during the bridge attachment. I'm attaching the bridge during hotplug so only one connector create at a time.
Thanks, Jagan.
Hi Maxime,
On Thu, Mar 10, 2022 at 4:05 PM Maxime Ripard maxime@cerno.tech wrote:
On Wed, Mar 09, 2022 at 06:45:10PM -0600, Adam Ford wrote:
On Wed, Mar 9, 2022 at 1:11 PM Jagan Teki jagan@amarulasolutions.com wrote:
or a Hi All,
On Thu, Oct 14, 2021 at 6:45 PM Jagan Teki jagan@amarulasolutions.com wrote:
Hi Laurent,
On Fri, Oct 8, 2021 at 7:07 PM Laurent Pinchart laurent.pinchart@ideasonboard.com wrote:
Hello,
On Fri, Oct 08, 2021 at 03:27:43PM +0200, Andrzej Hajda wrote:
Hi,
Removed my invalid email (I will update files next week).
On 08.10.2021 13:14, Jagan Teki wrote: > Hi, > > I think this seems to be a known use case for industrial these days with i.mx8m. > > The host DSI would configure with two bridges one for DSI to LVDS > (SN65DSI83) and another for DSI to HDMI Out (ADV7535). Technically we > can use only one bridge at a time as host DSI support single out port. > So we can have two separate device tree files for LVDS and HDMI and > load them static. > > But, one of the use cases is to support both of them in single dts, and > - Turn On LVDS (default) > - Turn Off LVDS then Turn On HDMI when cable plug-in
Are you sure it will work from hardware PoV? Do you have some demuxer? isolation of pins?
It may be in the category of "you shouldn't do this, but it actually works". I've seen the same being done with two CSI-2 camera sensors connected to the same receiver, with one of them being held in reset at all times.
Yes. Here the design has 2 MIPI D-PHY switches. Each switch take 2 input data lanes and 1 clock lane from SoC and produces 4 data lanes and 2 clock lanes and from switch output 2 lanes and 1 clock are inputting to HDMI bridge and other 2 lanes and 1 clock is inputting to LVDS. So 1st pair of 1st switch and 1st pair of 2nd switch goes to HDMI and 2nd pair of 1st switch and 2nd pair of 2nd switch does to LVDS.
However, routing of these lanes are controlled by SEL, OE GPIO pins. So at a time we can access only single bridge.
> The HDMI event can be detected via some HDMI-INT GPIO on-board design. > > The possible solution, I'm thinking of adding LVDS on port 1, HDMI on > port 2 in the DSI host node, and trying to attach the respective > bridge based on HDMI-INT like repeating the bridge attachment cycle > based on the HDMI-INT.
I think more appropriate would be to share the same port, but provide two endpoints inside this port - we have two hardware sharing the same physical port.
That sounds like the correct DT description to me.
> Can it be possible to do bridge attachment at runtime? something like > a bridge hotplug event? or any other possible solutions? > > Any suggestions?
Practically it is possible, see exynos_dsi + panels, or exynos_dsi + some toshiba bridge - panel and bridge are dynamically 'plugged' and 'unplugged' from exynos_drm, but they do not use bridge chain for this and some other reasons. (un|re|)plugging should be performed of course when pipeline is off (connector disconnected). I am not sure about bridges added to bridge chain - you need to inspect all opses to ensure it can be done safely.
And the main issue: Daniel does not like it :)
Neither do I :-) Could it be handled with two DRM connectors that are mutually exclusive ?
How about adding lvds-connector, hdmi-connector on the pipeline and select them based on the switch SEL GPIO? does it make sense to do this implementation via display-connector.c
I have somehow managed to make runtime switching possible between LVDS and HDMI with the help of DRM bridges.
| => ADV7535 =>HDMI-A Connector DSI Host => display-switch => | |=> SN65DSI83 => Panel-Simple
display-switch here is a bridge driver that can switch or attach the downstream bridge flow based on HDMI HPD here. One potential problem is that when we switch from LVDS to HDMI Out the HDMI Out is displayed with the resolution that LVDS has and it is unable to display higher HDMI resolutions even though it supports it. Does anyone aware of changing the resolution at runtime, please let me know?
Technically, the display-switch hardware does available in various forms
- MIPI Switch PI3WVR626
- Conventional Mux Switch
- Converter bridge DSI to LVDS/HDMI (from Lontium).
Overall I believe this can be a potential possible feature and good to support on Mainline as the hardware is intended to design for it.
Any thoughts on this please let me know?
I wonder if it would be possible to trigger a hot plug event similar to what is done when an HDMI cable is inserted/disconnected.
If one switches, force a disconnect event, then triggle the connection event to force the video system to rescan/attach. I am not sure how to go about implementing such a thing, but that's my first thought
Nothing prevents the DRM Master to just ignore the hotplug event though :) Kodi does that for example.
I think we could simply create two connectors, one for LVDS, one for HDMI, with atomic_check making sure only one of them is enabled at the same time?
The one thing that would make it difficult is that we're changing the bridge list to a tree. For example, in such a case, what should drm_bridge_get_next_bridge return? This will obviously depend on the state, but it's used in context were we don't have a state (such as drm_bridge_connector_init).
From display-switch bridge, we can have a tree of one bridge chain for
HDMI and another bridge chain for LVDS ended with respective connectors but how to attach the respective down-stream bridges of the tree and get the associated connector? does "state" in the above mean to preserve each bridge chain path in order to get the proper connector?
I tried to attach the down-stream bridge one after another in for loop from display-switch. Both attached and last bridge in the loop get enabled with LVDS-1 and HDMI-A-1 connectors are created but the last bridge chain is tailed with the first, not like the tree - like display-switch => lvds bridge => hdmi bridg.
Any suggestions?
Jagan.
On Thu, Mar 10, 2022 at 6:15 AM Adam Ford aford173@gmail.com wrote:
On Wed, Mar 9, 2022 at 1:11 PM Jagan Teki jagan@amarulasolutions.com wrote:
or a Hi All,
On Thu, Oct 14, 2021 at 6:45 PM Jagan Teki jagan@amarulasolutions.com wrote:
Hi Laurent,
On Fri, Oct 8, 2021 at 7:07 PM Laurent Pinchart laurent.pinchart@ideasonboard.com wrote:
Hello,
On Fri, Oct 08, 2021 at 03:27:43PM +0200, Andrzej Hajda wrote:
Hi,
Removed my invalid email (I will update files next week).
On 08.10.2021 13:14, Jagan Teki wrote:
Hi,
I think this seems to be a known use case for industrial these days with i.mx8m.
The host DSI would configure with two bridges one for DSI to LVDS (SN65DSI83) and another for DSI to HDMI Out (ADV7535). Technically we can use only one bridge at a time as host DSI support single out port. So we can have two separate device tree files for LVDS and HDMI and load them static.
But, one of the use cases is to support both of them in single dts, and
- Turn On LVDS (default)
- Turn Off LVDS then Turn On HDMI when cable plug-in
Are you sure it will work from hardware PoV? Do you have some demuxer? isolation of pins?
It may be in the category of "you shouldn't do this, but it actually works". I've seen the same being done with two CSI-2 camera sensors connected to the same receiver, with one of them being held in reset at all times.
Yes. Here the design has 2 MIPI D-PHY switches. Each switch take 2 input data lanes and 1 clock lane from SoC and produces 4 data lanes and 2 clock lanes and from switch output 2 lanes and 1 clock are inputting to HDMI bridge and other 2 lanes and 1 clock is inputting to LVDS. So 1st pair of 1st switch and 1st pair of 2nd switch goes to HDMI and 2nd pair of 1st switch and 2nd pair of 2nd switch does to LVDS.
However, routing of these lanes are controlled by SEL, OE GPIO pins. So at a time we can access only single bridge.
The HDMI event can be detected via some HDMI-INT GPIO on-board design.
The possible solution, I'm thinking of adding LVDS on port 1, HDMI on port 2 in the DSI host node, and trying to attach the respective bridge based on HDMI-INT like repeating the bridge attachment cycle based on the HDMI-INT.
I think more appropriate would be to share the same port, but provide two endpoints inside this port - we have two hardware sharing the same physical port.
That sounds like the correct DT description to me.
Can it be possible to do bridge attachment at runtime? something like a bridge hotplug event? or any other possible solutions?
Any suggestions?
Practically it is possible, see exynos_dsi + panels, or exynos_dsi + some toshiba bridge - panel and bridge are dynamically 'plugged' and 'unplugged' from exynos_drm, but they do not use bridge chain for this and some other reasons. (un|re|)plugging should be performed of course when pipeline is off (connector disconnected). I am not sure about bridges added to bridge chain - you need to inspect all opses to ensure it can be done safely.
And the main issue: Daniel does not like it :)
Neither do I :-) Could it be handled with two DRM connectors that are mutually exclusive ?
How about adding lvds-connector, hdmi-connector on the pipeline and select them based on the switch SEL GPIO? does it make sense to do this implementation via display-connector.c
I have somehow managed to make runtime switching possible between LVDS and HDMI with the help of DRM bridges.
| => ADV7535 =>HDMI-A Connector DSI Host => display-switch => | |=> SN65DSI83 => Panel-Simple
display-switch here is a bridge driver that can switch or attach the downstream bridge flow based on HDMI HPD here. One potential problem is that when we switch from LVDS to HDMI Out the HDMI Out is displayed with the resolution that LVDS has and it is unable to display higher HDMI resolutions even though it supports it. Does anyone aware of changing the resolution at runtime, please let me know?
Technically, the display-switch hardware does available in various forms
- MIPI Switch PI3WVR626
- Conventional Mux Switch
- Converter bridge DSI to LVDS/HDMI (from Lontium).
Overall I believe this can be a potential possible feature and good to support on Mainline as the hardware is intended to design for it.
Any thoughts on this please let me know?
I wonder if it would be possible to trigger a hot plug event similar to what is done when an HDMI cable is inserted/disconnected.
If one switches, force a disconnect event, then triggle the connection event to force the video system to rescan/attach. I am not sure how to go about implementing such a thing, but that's my first thought
HDP on the connector can be useful in order to switch the displays like 1 and 2 cases listed above. However, that is indeed a difficult task for the pipline establishment as switch selection has to be done before the output bridge and after the host bridge - This is one of the reasons I've tried the implementation in the form via display-connector. One more important accept here is the like bridge-selection in above case 3 has dedicated interrupt gpio to route the video data to LVDS or HDMI which is not related to HDMI-HPD.
Thanks, Jagan.
Hi Andrzej,
On Fri, Oct 8, 2021 at 6:57 PM Andrzej Hajda andrzej.hajda@gmail.com wrote:
Hi,
Removed my invalid email (I will update files next week).
On 08.10.2021 13:14, Jagan Teki wrote:
Hi,
I think this seems to be a known use case for industrial these days with i.mx8m.
The host DSI would configure with two bridges one for DSI to LVDS (SN65DSI83) and another for DSI to HDMI Out (ADV7535). Technically we can use only one bridge at a time as host DSI support single out port. So we can have two separate device tree files for LVDS and HDMI and load them static.
But, one of the use cases is to support both of them in single dts, and
- Turn On LVDS (default)
- Turn Off LVDS then Turn On HDMI when cable plug-in
Are you sure it will work from hardware PoV? Do you have some demuxer? isolation of pins?
Correct. I have noticed after you mentioned this. Design has two 2:1 MIPI Switch PI3WVR626 [1] which take 2 data-lanes and clock from Host and produce 4 data-lane and 1 clock to connect to ADV7535 and SN65DSI84 bridges.
The switch has OE, SEL pins to select the desired to MUXed lanes/clock routing to an appropriate bridge.
The HDMI event can be detected via some HDMI-INT GPIO on-board design.
The possible solution, I'm thinking of adding LVDS on port 1, HDMI on port 2 in the DSI host node, and trying to attach the respective bridge based on HDMI-INT like repeating the bridge attachment cycle based on the HDMI-INT.
I think more appropriate would be to share the same port, but provide two endpoints inside this port - we have two hardware sharing the same physical port.
Make sense to me. I think we can in-corporate the MIPI Switch on the pipeline as input data and clock lanes are muxing. not sure how it can be done.
Can it be possible to do bridge attachment at runtime? something like a bridge hotplug event? or any other possible solutions?
Any suggestions?
Practically it is possible, see exynos_dsi + panels, or exynos_dsi + some toshiba bridge - panel and bridge are dynamically 'plugged' and 'unplugged' from exynos_drm, but they do not use bridge chain for this and some other reasons. (un|re|)plugging should be performed of course when pipeline is off (connector disconnected). I am not sure about bridges added to bridge chain - you need to inspect all opses to ensure it can be done safely.
I will check with this. However i did tried of hot-plug mechanism for bridge in exiting DSI host sun6i_mipi_dsi.c [2] look like it surely not possible with bridge-chain as hot-plug require drm pointer where the same pointer is not available during attach call.
And the main issue: Daniel does not like it :)
[1] https://www.diodes.com/assets/Datasheets/PI3WVR626.pdf [2] https://elixir.bootlin.com/linux/v5.15-rc4/source/drivers/gpu/drm/sun4i/sun6...
Jagan.
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