vc4: HDMI Sink doesn't support RGB, something's wrong.

[Maíra Canal]

Hi,

On 14/10/24 18:16, Stefan Wahren wrote:
> 
> Am 14.10.24 um 12:54 schrieb Dave Stevenson:
>> On Mon, 14 Oct 2024 at 10:04, Maxime Ripard <mripard at kernel.org> wrote:
>>> Hi,
>>>
>>> On Sun, Oct 13, 2024 at 09:57:58PM GMT, Stefan Wahren wrote:
>>>> Am 13.10.24 um 21:11 schrieb Dave Stevenson:
>>>>> Hi Stefan.
>>>>>
>>>>> On Sun, 13 Oct 2024, 18:19 Stefan Wahren, <wahrenst at gmx.net> wrote:
>>>>>
>>>>>      Hi,
>>>>>
>>>>>      i recently switch for my suspend2idle tests from Raspberry Pi 
>>>>> Bullseye
>>>>>      to Bookworm. After that testing suspend2idle shows a new warning
>>>>>      which i
>>>>>      never saw before:
>>>>>
>>>>>      HDMI Sink doesn't support RGB, something's wrong.
>>>>>
>>>>>
>>>>> Can you provide the edid of your display please?
> ...
>>>>
>>>>
>>>> The failure is coming from sink_supports_format_bpc()[1], but the flag
>>>> for DRM_COLOR_FORMAT_RGB444 should have been set from
>>>> update_display_info()[2] parsing the EDID.
>>>>
>>>> Loading that EDID in via drm.edid_firmware has given me a console at
>>>> 1920x1200 at 60 without any issues, so I'm a little confused as to what
>>>> is going on.
> Since this warning only occurs on resume and not during normal boot, i
> would assume there is no issue with EDID. Maybe the flag get lost. I
> should have mention that X11 doesn't recover in this case and the
> display stays black.

The same warning appeared to me when running a kernel built on top of
drm-misc-next on a RPi 4B+. But, in my case, it happened during normal
boot.

The warning showed non-stop and it only stopped appearing when I
switched displays. In the first case (when the warning was happening), I
was using a USB video capture device to get the HDMI output. Then, I
switched to a real display and the warning stopped showing.

Best Regards,
- Maíra

>>>>
>>>>    Dave
>>>>
>>>> [1] 
>>>> https://elixir.bootlin.com/linux/v6.12-rc2/source/drivers/gpu/drm/display/drm_hdmi_state_helper.c#L130
>>>> [2] 
>>>> https://elixir.bootlin.com/linux/v6.12-rc2/source/drivers/gpu/drm/drm_edid.c#L6669
>