Messages in this thread | | | Date | Fri, 2 Jul 2010 16:12:30 -0700 | From | Jesse Barnes <> | Subject | Re: [PATCH] Implement direct pineview backlight control. |
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On Tue, 22 Jun 2010 16:58:27 -0700 Bryan Freed <bfreed@chromium.org> wrote:
> drm/i915: Add a direct interface for pineview backlight support. > > This adds a Kconfig variable CONFIG_DRM_I915_DIRECT_BACKLIGHT to > optionally include the new source file i915_backlight.c. This file > registers a couple backlight set/get routines with the standard > drivers/video/backlight interface to add a directory under > /sys/class/backlight/. > > The big problem I see with this modification is that the i915 driver > _already_ supports backlight level adjustment in i915_opregion.c. > Unfortunately, that requires an IRQ to occur as the result of writing > some ASLE (ACPI Source Language Event) register, and this requires > BIOS support for the ACPI hook. It looks like we will not have such > support in our initial custom BIOS. > > So I copy a small amount of code from i915_opregion.c to make backlight > adjustment directly available to the backlight framework. > > Another problem is that I do not cover all the cases handled by the > i915_opregion.c code. It would be too much untested code copying to > do so. I enforce the lack of support by checking for IS_PINEVIEW() > in i915_backlight_init(). > > Review URL: http://codereview.chromium.org/2830015 > Signed-off-by: Bryan Freed <bfreed@chromium.org>
How does this compare to Matthew's native backlight support? AFAIK that patch is still outstanding due to the need for some changes to the backlight subsystem.
Matthew?
-- Jesse Barnes, Intel Open Source Technology Center
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