Hi,
Am 10.01.24 um 11:11 schrieb Andri Yngvason:
Hi,
mið., 10. jan. 2024 kl. 09:27 skrifaði Maxime Ripard <mripard@xxxxxxxxxx>:
On Tue, Jan 09, 2024 at 06:11:02PM +0000, Andri Yngvason wrote:
From: Werner Sembach <wse@xxxxxxxxxxxxxxxxxxx>
Add a new general drm property "preferred color format" which can be used
by userspace to tell the graphic drivers to which color format to use.
Possible options are:
- auto (default/current behaviour)
- rgb
- ycbcr444
- ycbcr422 (not supported by both amdgpu and i915)
- ycbcr420
In theory the auto option should choose the best available option for the
current setup, but because of bad internal conversion some monitors look
better with rgb and some with ycbcr444.
I looked at the patch and I couldn't find what is supposed to happen if
you set it to something else than auto, and the driver can't match that.
Are we supposed to fallback to the "auto" behaviour, or are we suppose
to reject the mode entirely?
The combination with the active output format property suggests the
former, but we should document it explicitly.
It is also my understanding that it should fall back to the "auto"
behaviour. I will add this to the documentation.
Yes, that was the intention, and then userspace can check, but it wasn't well
received: https://gitlab.freedesktop.org/drm/amd/-/issues/476#note_964530
Actually a lot of the thoughts that went into the original patch set can be
found in that topic.
There was another iteration of the patch set that I never finished and sent to
the LKML because I got discouraged by this:
https://lore.kernel.org/dri-devel/20210623102923.70877c1a@eldfell/
I can try to dig it up, but it is completely untested and I don't think I still
have the respective TODO list anymore, so I don't know if it is a better or
worst starting point than the last iteration I sent to the LKML.
Greetings
Werner
Thanks,
Andri
