Messages in this thread | | | From | Jani Nikula <> | Subject | Re: [Intel-gfx] Linux 3.11-rc2 [backlight] [ASUS N56VZ] | Date | Thu, 25 Jul 2013 11:09:27 +0300 |
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On Thu, 25 Jul 2013, "Rafael J. Wysocki" <rjw@sisk.pl> wrote: > On Wednesday, July 24, 2013 02:05:15 PM Linus Torvalds wrote: >> On Wed, Jul 24, 2013 at 2:02 PM, Daniel Vetter <daniel.vetter@ffwll.ch> wrote: >> > >> > I think a i915 module option should be doable, otoh people seem to have a >> > viable workaround by setting a different acpi os version already. >> >> At least the original claim was that if you set a non-windows8 acpi os >> version, you hit other bugs.. >> >> But yeah, if we just do a plain revert, that may be the only option >> for the people for whom the current (to-be-reverted) patches made >> things work. > > Well, I wonder what about the appended (untested) patch?
Rafael, before going there, I've been trying to wrap my (poor, rusty after vacation) head around
commit 8c5bd7adb2ce47e6aa39d17b2375f69b0c0aa255 Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Date: Thu Jul 18 02:08:06 2013 +0200
ACPI / video / i915: No ACPI backlight if firmware expects Windows 8
and I can't see how it could work.
First, the ACPI_VIDEO_SKIP_BACKLIGHT flag seems to be checked before it's actually set anywhere. Buried deep in the calls from acpi_video_bus_add(), acpi_video_verify_backlight_support() is used before acpi_video_backlight_quirks() gets called. (Perhaps if i915 is reloaded, this goes right as the flags are already set.)
Second, with i915 that has opregion support, __acpi_video_register() should only ever get called once. Which means the acpi_walk_namespace() with video_unregister_backlight() should never get called in register.
Please enlighten me.
BR, Jani.
-- Jani Nikula, Intel Open Source Technology Center
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