https://bugzilla.kernel.org/show_bug.cgi?id=81691
Bug ID: 81691 Summary: Regression: Thinkpad T420 brightness keys broken by commit 751109aad, video.use_native_backlight=1 Product: ACPI Version: 2.5 Kernel Version: 3.16 (since commit 751109aad) Hardware: x86-64 OS: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: Power-Video Assignee: acpi_power-vi...@kernel-bugs.osdl.org Reporter: andre.mul...@web.de Regression: No Created attachment 145151 --> https://bugzilla.kernel.org/attachment.cgi?id=145151&action=edit output of dmidecode, xz compressed In linux-3.16, this commit > commit 751109aad5834375ca9ed0dcfcd85a00cbf872b5 > Author: Rafael J. Wysocki <rafael.j.wyso...@intel.com> > Date: Thu Jun 5 22:47:35 2014 +0200 > > ACPI / video: Change the default for video.use_native_backlight to 1 breaks backlight control on the Lenovo Thinkpad T420. That is, I can't change brightness via the Fn-Keys anymore. Writing to /sys/devices/pci0000:00/0000:00:02.0/drm/card0/card0-LVDS-1/intel_backlight/brightness works, but the kernel should just handle it by itself. Providing video.use_native_backlight=0 on the kernel command line fixes the controls. So this would need to get a quirk or a fix for native backlight. I do attach the dmidecode output. I'll happily provide more information, or test things. -- You are receiving this mail because: You are watching the assignee of the bug. ------------------------------------------------------------------------------ Infragistics Professional Build stunning WinForms apps today! Reboot your WinForms applications with our WinForms controls. Build a bridge from your legacy apps to the future. http://pubads.g.doubleclick.net/gampad/clk?id=153845071&iu=/4140/ostg.clktrk _______________________________________________ acpi-bugzilla mailing list acpi-bugzilla@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/acpi-bugzilla