Created attachment 131413 [details] dmesg with debug enabled With 4.12-rc1 the screen goes dark during boot when attempting to modeswitch. I assume the backlight is turned off. Still worked with kernel 4.11. This is on a baytrail tablet.
Bisect would really be helpful here.
Indeed it would, but doing a full bisect takes way too long to compile and test. If you have a list of commits that went into 4.12-rc1 and might be relevant to test I can do a few builds and try those.
Created attachment 131605 [details] dmesg 4.12-rc3 display on I tried the 4.12-rc3 to check if anything has changed. Screen still goes dark most of the time. However maybe 1 in 5 boots the screen stays on with full brightness. So this might be a race. Attaching another dmesg of a successful boot with screen staying on.
Did your kernel config change? Possibly dupe of bug 96571. I believe that might manifest itself as a race too.
kernel config stayed the same, no change there. Any way for me to confirm if this is indeed a dupe of bug 96571? I have CONFIG_PWM_LPSS=m CONFIG_PWM_LPSS_PCI=m CONFIG_PWM_LPSS_PLATFORM=m Also any patches I could test on top of 4.12? I see a lot of patch references in the other bz but not sure what's relevant.
Set config options >CONFIG_PWM=y >CONFIG_PWM_CRC=y >CONFIG_I2C_DESIGNWARE_PLATFORM=y >CONFIG_I2C_DESIGNWARE_PCI=y >CONFIG_INTEL_SOC_PMIC=y >CONFIG_DRM_I915=m and see if it helps.
The only difference to my config was that I had CONFIG_I2C_DESIGNWARE_PLATFORM=m CONFIG_I2C_DESIGNWARE_PCI=m instead of =y. However changing those to =y didn't make a difference. Would any intel-gpu-tools output be useful?
Seeing your comment in bug 96571, can we assume this is a dupe?
Yes, correct.
(In reply to sassmann from comment #9) > Yes, correct. Marking as duplicated. Please keep following the case on 96571 . Thank you. *** This bug has been marked as a duplicate of bug 96571 ***
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