Re: [REGRESSION] bisected: 7.1rc1 breaks backlight control on Thinkpad T480
Thorsten Leemhuis <[email protected]>
| Newsgroups | dev.linux.lists.regressions,org.kernel.vger.linux-kernel |
|---|---|
| Message-ID | <[email protected]> |
On 5/15/26 13:47, Stefan Seyfried wrote: > > I found that 7.1rc1 broke the backlight control on my Thinkpad T480. > Bisected it to > >> 40d2f5820951dee818d05c14677277048bd85f9f is the first bad commit >> commit 40d2f5820951dee818d05c14677277048bd85f9f >> Author: Suraj Kandpal <[email protected]> >> Date: Tue Feb 24 08:43:22 2026 +0530 >> >> drm/i915/backlight: Remove try_vesa_interface FWIW: Here are two bug reports that contain proposed fixes for what might or might not be the issue your face: https://gitlab.freedesktop.org/drm/i915/kernel/-/work_items/16043 https://gitlab.freedesktop.org/drm/i915/kernel/-/work_items/16015 Ciao, Thorsten >> Some panels need VESA DPCD AUX backlight but VBT says otherwise. >> This is why we try with Intel backlight interface over VESA backlight >> interface. This causes a blankout on such panels without any fallback >> mechanism. >> Remove try_vesa_interface and use VESA AUX backlight interface as a >> fallback mechanism. >> While at in sneak in a small comment cleanup too. >> Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/ >> issues/15679 >> Signed-off-by: Suraj Kandpal <[email protected]> >> Reviewed-by: Ankit Nautiyal <[email protected]> >> Link: https://patch.msgid.link/20260224031322.2568874-1- >> [email protected] >> >> drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c | 19 ++++++ >> +------------ >> 1 file changed, 7 insertions(+), 12 deletions(-) > > Please revert :-) > > Best regards,