On Monday, July 13, 2026 12:56:39 PM Central European Summer Time Thorsten Leemhuis wrote: > On 7/13/26 12:00, Timur Kristóf wrote: > > On Monday, July 13, 2026 10:28:08 AM Central European Summer Time Thorsten > > > > Leemhuis wrote: > >> On 7/13/26 08:14, Timur Kristóf wrote: > >>> What I expected to happen is that the GPU would simply use > >>> its maximum memory clock, and indeed this is what seemed > >>> to happen according to amdgpu_pm_info which reads the > >>> current MCLK value from the SMU. > >>> However, some users reported a huge perf regression > >> > >> Were those private reports? If not, please consider linking them in the > >> trailers using Link: or Closes: tags, as explained in the patch > >> submission guidelines (and mandated by Linus, see the quotes and links > >> in > >> https://www.kernel.org/doc/html/latest/process/handling-regressions.html# > >> on-> the-importance-of-pointing-to-bug-reports-using-link-closes-tags for > >> details). > > Thx for the reply! > > > There is no bug report. I had a conversation on Reddit which brought my > > attention to this issue, then I actually plugged in the GPU, tested it and > > noticed that there is indeed a problem, > > FWIW, we occasionally link to reddit threads as well, but sounds like > this would not make sense here.
There are no details about this on Reddit. I just heard that somebody experienced a slowdown with this specific GPU starting from the time when my previous patch was backported and I realized the PCI ID matches what I added in my previous patch. So I got suspicious that maybe it doesn't work as I had thought. Then I just tested it for myself and found what I explained in the commit message here. I apologize for the trouble. > > BTW (feel free to ignore this if you have no idea): I first had wondered > if there is a bug report about this in > https://gitlab.freedesktop.org/drm/amd/-/work_items and wanted to search > if the culprit was mentioned anywhere. Do you by chance know if that is > somehow possible? GitLab can show when a commit was mentioned, if it's a commit hash that the specific GitHub instance knows about. However I'm not sure how reliable that is, because the same commit may have a different hash depending on which tree you are working with. It may not know that the different hashes are really the same commit. > > To provide an example of what I want: > > https://gitlab.freedesktop.org/drm/i915/kernel/-/work_items/16043#note_35638 > 09 mentions commit-id 2914709c (Revert "drm/i915/backlight: Remove > try_vesa_interface"") -- but I didn't find a way to find tickets then > refer to that commit, for example with a search like this: > https://gitlab.freedesktop.org/search?search=2914709c&nav_source=navbar&sear > ch_code=true > > Is there some trick to do this? For that example, if you open the commit link: https://gitlab.freedesktop.org/drm/i915/kernel/-/commit/ 2914709c914101eb704e01bed2351070d4161ccf You can scroll down and see that the commit was mentioned, and you can then click on the issues where it was mentioned. Hope this helps, Timur
