On Tue, 22 Jun 2021 19:06:43 +0200 Werner Sembach <wse@xxxxxxxxxxxxxxxxxxx> wrote: > Am 19.05.21 um 11:34 schrieb Pekka Paalanen: > > On Wed, 12 May 2021 16:04:16 +0300 > > Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> wrote: > > > >> On Wed, May 12, 2021 at 02:06:56PM +0200, Werner Sembach wrote: > >>> Hello, > >>> > >>> In addition to the existing "max bpc", and "Broadcast RGB/output_csc" drm properties I propose 4 new properties: > >>> "preferred pixel encoding", "active color depth", "active color range", and "active pixel encoding" > >>> > >>> > >>> Motivation: > >>> > >>> Current monitors have a variety pixel encodings available: RGB, YCbCr 4:4:4, YCbCr 4:2:2, YCbCr 4:2:0. > >>> > >>> In addition they might be full or limited RGB range and the monitors accept different bit depths. > >>> > >>> Currently the kernel driver for AMD and Intel GPUs automatically configure the color settings automatically with little > >>> to no influence of the user. However there are several real world scenarios where the user might disagree with the > >>> default chosen by the drivers and wants to set his or her own preference. > >>> > >>> Some examples: > >>> > >>> 1. While RGB and YCbCr 4:4:4 in theory carry the same amount of color information, some screens might look better on one > >>> than the other because of bad internal conversion. The driver currently however has a fixed default that is chosen if > >>> available (RGB for Intel and YCbCr 4:4:4 for AMD). The only way to change this currently is by editing and overloading > >>> the edid reported by the monitor to the kernel. > >>> > >>> 2. RGB and YCbCr 4:4:4 need a higher port clock then YCbCr 4:2:0. Some hardware might report that it supports the higher > >>> port clock, but because of bad shielding on the PC, the cable, or the monitor the screen cuts out every few seconds when > >>> RGB or YCbCr 4:4:4 encoding is used, while YCbCr 4:2:0 might just work fine without changing hardware. The drivers > >>> currently however always default to the "best available" option even if it might be broken. > >>> > >>> 3. Some screens natively only supporting 8-bit color, simulate 10-Bit color by rapidly switching between 2 adjacent > >>> colors. They advertise themselves to the kernel as 10-bit monitors but the user might not like the "fake" 10-bit effect > >>> and prefer running at the native 8-bit per color. > >>> > >>> 4. Some screens are falsely classified as full RGB range wile they actually use limited RGB range. This results in > >>> washed out colors in dark and bright scenes. A user override can be helpful to manually fix this issue when it occurs. > >>> > >>> There already exist several requests, discussion, and patches regarding the thematic: > >>> > >>> - https://gitlab.freedesktop.org/drm/amd/-/issues/476 > >>> > >>> - https://gitlab.freedesktop.org/drm/amd/-/issues/1548 > >>> > >>> - https://lkml.org/lkml/2021/5/7/695 > >>> > >>> - https://lkml.org/lkml/2021/5/11/416 > >>> > > ... > > > >>> Adoption: > >>> > >>> A KDE dev wants to implement the settings in the KDE settings GUI: > >>> https://gitlab.freedesktop.org/drm/amd/-/issues/476#note_912370 > >>> > >>> Tuxedo Computers (my employer) wants to implement the settings desktop environment agnostic in Tuxedo Control Center. I > >>> will start work on this in parallel to implementing the new kernel code. > >> I suspect everyone would be happier to accept new uapi if we had > >> multiple compositors signed up to implement it. > > I think having Weston support for these would be good, but for now it > > won't be much of an UI: just weston.ini to set, and the log to see what > > happened. > > Since a first version of the patch set is now feature complete, > please let me know if a MR regarding this is started. I'll try to remember that if I see someone else do it, but I'm also pretty sure I won't be writing it any time soon. Still a long way until it would be used with the color management work. Thanks, pq
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