On Tue, Jul 22, 2014 at 8:42 AM, Hans de Goede <hdegoede@xxxxxxxxxx> wrote: > Hi Jani et al, > > A friend of mine Bertrik Sikken (in the Cc) his backlight control > stopped working for him on his Samsung N150Plus netbook. > > I took a quick look, and the raw intel_backlight backlight interface > works under 3.14, but the firmware samsung_laptop backlight interface, > which is what most userspace apps will use by default, stops working > in 3.14 . > > I've asked him to bisect this and the bisect points out this > commit as the culprit: > > b35684b8fa94e04f55fd38bf672b737741d2f9e2 is the first bad commit > commit b35684b8fa94e04f55fd38bf672b737741d2f9e2 > Author: Jani Nikula <jani.nikula@xxxxxxxxx> > Date: Thu Nov 14 12:13:41 2013 +0200 > > drm/i915: do full backlight setup at enable time > > We should now have all the information we need to do a full > initialization of the backlight registers. > > v2: Keep QUIRK_NO_PCH_PWM_ENABLE for now (Imre). > > Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx> > Reviewed-by: Imre Deak <imre.deak@xxxxxxxxx> > Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxx> > > Note that this laptop has an acpi_video backlight interface too, > but that has been broken from the start and gets disabled by > samsung-laptop based on dmi matching. How does the intel backlight fare? Please test both 3.14 and 3.15 and also test what happens when you blacklist the samsung-laptop driver (if that's possible without wreaking the machine). Also please grab latest intel-gpu-tools and record a register dump with intel_reg_dump, again for both broken and working kernels. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
