Control: forwarded -1 https://lore.kernel.org/regressions/[email protected]
Hi Jaak Ristioja reported the following issue in Debian at https://bugs.debian.org/1139950 . Part of the original report contains Debian specific version information, but Jaak did as well a bisecion for the regression see below: On Sun, Jun 14, 2026 at 02:27:01AM +0300, Jaak Ristioja wrote: > Package: linux-modules-7.0.10+deb13-amd64 > Version: 7.0.10-1~bpo13+1 > > Hi, > > Upgrading (after a long while) Debian Trixie installations on two different > HP EliteDesk 705 G4 DM 35W computers with AMD PRO A10-9700E R7 (carrizo) > resulted in both machines blanking the screen right after kernel modesetting > activates via amdgpu, with the monitor reporting "no signal". There are no > other symptoms besides losing the display as the system continues to run and > is accessible using keyboard and network. > > Bug first discovered with stable kernel linux-image-6.12.90+deb13.1-amd64 > (6.12.90-2) and the one from trixie-backports. The device is connected to a > monitor using a DisplayPort to HDMI adapter. The bug occurs regardless of > which if the two available physical DisplayPort ports to use. > > I don't remember this being an issue some months ago, so I tried to > reproduce this booting the Debian 13.1.0 and 13.4.0 install DVD images and > using the kernel modules/firmware therein: > > 13.1.0 installer: > firmware-amd-graphics_20250410-2 > linux-image-6.12.43+deb13-amd64_6.12.43-1 > 13.4.0 installer: > firmware-amd-graphics 20250410-2 > linux-image-6.12.73+deb13-amd64_6.12.73-1 > > I essentially unpacked the two *.deb files manually, depmod -a; modprobe drm > debug=0x1ff; modprobe amdgpu. > > I observed the bug reproduce using the 13.4.0 installer, but not on the > 13.1.0 installer, meaning this is a regression somewhere between kernel > versions 6.12.43-1 and 6.12.73-1. The reporter did a bisection and found as offending commit: drm/amd/display: Bump the HDMI clock to 340MHz commit fee50077656d8a58011f13bca48f743d1b6d6015 upstream. [Why] DP-HDMI dongles can execeed bandwidth requirements on high resolution monitors. This can lead to pruning the high resolution modes. HDMI 1.3 bumped the clock to 340MHz, but display code never matched it. [How] Set default to (DVI) 165MHz. Once HDMI display is identified update to 340MHz. Reported-by: Dianne Skoll <[email protected]> Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/4780 Reviewed-by: Chris Park <[email protected]> Signed-off-by: Mario Limonciello <[email protected]> Signed-off-by: Matthew Stewart <[email protected]> Tested-by: Dan Wheeler <[email protected]> Signed-off-by: Alex Deucher <[email protected]> (cherry picked from commit ac1e65d8ade46c09fb184579b81acadf36dcb91e) Cc: [email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]> Does this ring any bell? #regzbot introduced: ae5b1d291c814a2884c3d54a56e83bc99052b1eb #regzbot link: https://bugs.debian.org/1139950 Regards, Salvatore
