Summary: | i915.fastboot=1 breaks brightness control on my Thinkpad T540p (haswell) | ||
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Product: | Gentoo Linux | Reporter: | Anton Gubarkov <anton.gubarkov> |
Component: | Current packages | Assignee: | Gentoo Kernel Bug Wranglers and Kernel Maintainers <kernel> |
Status: | RESOLVED INVALID | ||
Severity: | normal | CC: | herrtimson, hydrapolic |
Priority: | Normal | ||
Version: | unspecified | ||
Hardware: | All | ||
OS: | Linux | ||
See Also: | https://bugs.freedesktop.org/show_bug.cgi?id=103781 | ||
Whiteboard: | |||
Package list: | Runtime testing required: | --- |
Description
Anton Gubarkov
2017-12-18 07:23:00 UTC
brightness controls do change /sys/class/backlight/intel_backlight/brightness value, but it doesn't affect the actual brightness of the panel. Plugging an external monitor immediately sets the panel brightness to the value of /sys/class/backlight/intel_backlight/brightness and further control becomes possible. Is it the same with vanilla sources? The culprit turned out to be the i915.fastboot=1 Please see https://bugs.freedesktop.org/show_bug.cgi?id=103781 |