On Thu, 25 Jul 2013, "Rafael J. Wysocki" <[email protected]> wrote: > On Wednesday, July 24, 2013 02:05:15 PM Linus Torvalds wrote: >> On Wed, Jul 24, 2013 at 2:02 PM, Daniel Vetter <[email protected]> >> 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 <[email protected]> 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
