On Wed, 23 Jul 2014, Hans de Goede <hdegoede@xxxxxxxxxx> wrote: > Hi, > > On 07/22/2014 08:52 AM, Daniel Vetter wrote: >> 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? > > That works fine with 3.14 . > >> Please test both 3.14 and 3.15 and > > We've tested with 3.14, please let us know if you also want > Bertrik to test with 3.15. > >> also test what happens when you blacklist the samsung-laptop driver >> (if that's possible without wreaking the machine). > > Then the vendor interface won't get promoted, acpi-video will load, > and things likely will not work. > > Bertrik, can you try blacklisting the samsung-laptop module, then > check /sys/class/backlight, the samsung_laptop dir should be gone > replaced by an acpi_video0 (or some such) dir. Please try if that > works. If that does not work, try booting with both the module > blacklisted and "acpi_backlight=vendor" on the kernel commandline, > then you should see only the intel-backlight under /sys/class/backlight > and things should work. > >> Also please grab latest intel-gpu-tools and record a register dump >> with intel_reg_dump, again for both broken and working kernels. > > Bertrik, can you do this please (without the blacklisting or special > kernel commandline options). Please attach dmesg with drm.debug=0xe module parameter set for some recent kernel. BR, Jani. > > Regards, > > Hans -- Jani Nikula, Intel Open Source Technology Center _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
