Hi,
so the 4:4:4 issue was just a gstreamer bug and it worked when I applied
an experimental fix [1].
So everything works for me using the default EDID now.
Tested-by: Tim Surber <me@xxxxxxxxxxxx>
[1]:
https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/8534
On 3/5/25 10:09, Dmitry Osipenko wrote:
On 3/5/25 12:03, Dmitry Osipenko wrote:
On 3/5/25 11:10, Hans Verkuil wrote:
On 05/03/2025 01:59, Tim Surber wrote:
Hi Dmitry,
I did some more testing. That the Apple TV did not work was a bit
misleading.
It was just, that the Apple TV defaulted to 4:4:4 Chroma which does not
work at all for me. (The same happens using the vendor driver).
When I changed the EDID to match the vendor driver the HDMI handshake
happened with 4:2:0 chroma, where I could verify even 4k60fps using your
driver, nice!
So the remaining problems I see are:
- 4:4:4 chroma not working in any resolution
- 4:2:2 and RGB not working in 4k60fps (is this a hardware limitation?)
A possible workaround could be to disable these non supported formats in
the default EDID.
I would like to merge this driver this week, since otherwise it will likely
slip to v6.16. So if there is a working EDID, perhaps it can be used for now,
and later on it can be patched if there is a better EDID.
Would this EDID work? Tim, can you try this?
v4l2-ctl --set-edid type=hdmi-4k-600mhz,ycbcr444,ycbcr422
Alternatively, if there is indeed a HW limitation that prevents 4kp60 to work,
try this:
v4l2-ctl --set-edid type=hdmi-4k-300mhz,ycbcr444,ycbcr422
Whichever of the two works is what we can use as default EDID.
Disabling 444 and 422 is an option. Though, they work on my setup at
4k@60p.
In general, it often a challenge to get 4k@60p properly with any of
these small board devices. 4k@60p works only using a short HDMI cable
for me. Also, not everyone aware that the micro HDMI adapter needs to be
compliant with HDMI 2.0 for 4k@60, that's why 300MHz is the default.
Will be nice to have the good EDID enabled by default in the defconfig.
Dealing with problems like that will be a headache for majority of
people, IMO.
BTW, I don't see it as a blocker. Driver works in general, new issues
can be resolved with additional patches.
