Re: [External Mail] Re: Test result / finding of "drm/amd/display: Consult MCCS FreeSync cap only if requested & supported"
Thorsten Leemhuis <[email protected]>
| Newsgroups | dev.linux.lists.regressions,org.freedesktop.lists.amd-gfx |
|---|---|
| Message-ID | <[email protected]> |
[+Alex +Christian] On 5/21/26 09:09, Michel Dänzer wrote: > On 5/20/26 17:54, Pei-Hsin Yang wrote: >> >>> Tested with 3 HDMI sinks with different FreeSync/HDMI VRR capabilities. I saw one case that a FreeSync sink (Dell S2721HS) with E6h VCP code supported was detected as FreeSync capable at beginning but identified as not FreeSync capable later – after do_mccs is changed from true to false. >> >>>> And that doesn't happen without my patch applied? >> >> There are other issues without your patch applied. One issue is that if a FreeSync capable sink with MCCS VCP Code = 0 (mostly are TVs), it will be detected as not FreeSync supported and VRR will be disabled. > > That sounds similar to https://gitlab.freedesktop.org/drm/amd/-/work_items/5286 . > > I was wondering if the specific issue you described above with Dell S2721HS is reproducible without my patch though, in which case it might be a separate regression (and wouldn't speak against merging my patch). > > >>>> TBH I don't really want to be fixing the regression I hit, I'd prefer the AMD display team to handle it. >> >> Yes, agreed. As FreeSync MCCS support has immediate impacts to Valve's Steam devices, I will work with AMD display team to handle it. HDMI 2.1 VRR and VTEM packet sending support need to be included as well. > > Note that some kind of short-term solution is needed for the regression(s) in 7.1-rc. Yeah, that would be good. Makes me wonder how the rough plan to realize this looks like? Sounds like Michael's patch[1] that was discussed here is not a good option? Reminder, Linus ideally wants known regression fixed by -rc6, which is why I'm asking. Ciao, Thorsten [1] https://lore.kernel.org/amd-gfx/[email protected]/