On Tue, Jun 23, 2015 at 1:44 PM, Russell King - ARM Linux linux@arm.linux.org.uk wrote:

If you have no connected connectors, then you get 1024x768:

imx-drm display-subsystem: No connectors reported connected with modes [drm] Cannot find any crtc or sizes - going 1024x768

as that's what DRM defaults to when it has no other timing information available.

Agreed, but after the cable is connected we could try to find a more suitable timing?

...

[ 16.310548] imx-ipuv3 2400000.ipu: videomode adapted for IPU restrictions

I don't see this message booting on a Hummingboard with HDMI disconnected.

I see this message in the following case:

- Boot the board with HDMI disconnected

- Connect the HDMI cable and then such message is displayed.

Thanks

On Tue, Jun 23, 2015 at 5:41 PM, Russell King - ARM Linux linux@arm.linux.org.uk wrote:

I've just tried this (the HBi1 was booted previously with the HDMI socket disconnected). Just now, I turned the TV on, and then connected it to the HDMI.

Thanks for testing it.

The TV reported a resolution of 1024x768, and the kernel log was silent.

That's the point that makes me confused: shouldn't it report a higher resolution like 1080p?

Why only 1024x768 even if the monitor supports higher resolution?

If we boot with the cable connected then it jumps to 1080.

My guess would be that your HDMI sink is reporting slightly non-standard 1024x768 timings, which cause the IPU restrictions to be violated. Maybe dumping the EDID of the HDMI device would reveal this?

# edid-decode < /sys/class/drm/card0-HDMI-A-1/edid

might provide some hints?

Thanks, will try it. Need to install this edid package in my rootfs.

On Tue, Jun 23, 2015 at 09:58:37PM +0100, Russell King - ARM Linux wrote:

On Tue, Jun 23, 2015 at 05:48:51PM -0300, Fabio Estevam wrote:

...

On Tue, Jun 23, 2015 at 5:41 PM, Russell King - ARM Linux linux@arm.linux.org.uk wrote:

...

I've just tried this (the HBi1 was booted previously with the HDMI socket disconnected). Just now, I turned the TV on, and then connected it to the HDMI.

Thanks for testing it.

...

The TV reported a resolution of 1024x768, and the kernel log was silent.

That's the point that makes me confused: shouldn't it report a higher resolution like 1080p?

No - it won't go higher than the initial mode that was set. See drm_fb_helper_hotplug_event():

    max_width = fb_helper->fb->width;
    max_height = fb_helper->fb->height;

    drm_fb_helper_probe_connector_modes(fb_helper, max_width, max_height);

This calls connector->funcs->fill_modes with the max width/height, which calls down into drm_helper_probe_single_connector_modes_merge_bits() and there's limitations in there which means that we won't try to increase the size of the framebuffer.

You do get that behaviour if you have the X server running, and that's all down to the X server itself doing that (reacting to the hotplug event which DRM generates.)

The initial fb allocated for fbdev emulation does indeed restrict what fbdev/con will show. But it should in now way affect the mode list (that's only the fbdev code doing the filtering there) or X. You should be able to list/set 1080p. Might be useful to figure out with drm.debug whether the mode was kicked out for some driver/hw restriction reason, that should get logged. -Daniel