On Thursday 01 Dec 2016 12:30:09 Jean-Francois Moine wrote:
On Thu, 01 Dec 2016 12:41:20 +0200 Laurent Pinchart wrote:
If a DVI connector instead of a HDMI connector is soldered, how should such a device tree be written?
Use a dvi-connector instead :)
The HDMI encoder DT node doesn't (and certainly shouldn't) report what type of connector is mounted on the board. Having a connector node in DT makes the connector type available to the system, allowing the DRM driver to expose the right connector type to userspace (it would be confusing for the user to report DRM_MODE_CONNECTOR_HDMIA for a DVI connector).
The connector type, HDMI or DVI, is known by the EDID. The user is not interested by the software indication of the connector type: (s)he knows it because (s)he connected him/herself the display device.
That's not correct. The connector type reported by DRM to userspace can be used as a hint to information the user about connectors. Displaying a "Please connect a monitor to the HDMI connector" is confusing when the system has a DVI connector.
And the DRM driver does not do anything from the knowledge of the connector type in the DT. Only the EDID may tell if the display device may do audio streaming (direct HDMI with audio capability) or not (direct HDMI without audio, HDMI to DVI cable, DVI physical connector).