On Tue, Mar 30, 2021, 1:33 AM Evan Leibovitch via talk, <
talk@gtalug.org> wrote:
Yeah, but it won't be about video cards (thankfully).
(FWIW, the issues I am having driving two 4K monitors with an RX 550 exist in both Windows and Linux, suggesting that it's not capable of driving both monitors at full spec. Either I need to dial down the frequency as Russell suggests, or I need a new horsepower card...)
IMO I think the issue is actually due the display EDID provided by many monitor / tv manufacturers is lacking in certain format/reporting respects. While linux autodetection generally works well in most use cases, this is the type of problem linux users have historically faced. I think this is probably due, not in any small part, to certain anti competetative practices.
Take for example the issues with devices using ccd. The lack of linux friendly colour profiles for ccd is one of the largest barriers to linux users in their choices of scanners and cameras etc.
I think in this case a closer look at the EDID for each monitor, assuming they are not exact duplicates of each other, may provide a workable solution. In fact it may be fixed already in a kernel/firmware upgrade.
If that is not possible/desirable then xrandr, get-edid and parse-edid will provide a better understanding of the autogeneration of the display modelines used by Xorg or whatever server is used.
In fact several solutions I have read in the past point to the fact that you can counterfit a manufactures EDID to overcome video tearing and flicker on both linux and windows.
I think linux tools for finer grained control of hi-def monitors are out there, you just have to figure out how to stitch them all together.
I just ran parse-edid on one of my machines EDID collection in /sys after booting into Debian Buster and it told me mine was not valid. The displays are working ok but neither of the Toshiba TV display or the dell monitor are new or 4k, so definately YMMV.