Re: [Intel-gfx] [RFC PATCH 0/2] i915 brightness control

[Jerone Young <jerone.young@canonical.com>]

On Thu, 2010-06-03 at 00:20 +0100, Pedro Ribeiro wrote:
> On 2 June 2010 23:11, Kamal Mostafa <kamal@canonical.com> wrote:
> > Requesting comments on this idea (proposed by Matthew Garrett) and my
> > implementation.  Note especially the KNOWN PROBLEM with a "GM45" GPU.
> >
> >  -Kamal
> >
> > .......
> >
> > BugLink: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/568611
> >
> > In order to avoid the often-dysfunctional native acpi brightness control
> > methods, a new acpi_brightness_hook interface is made available.
> >
> > The i915 driver uses the new hook to take over brightness control.
> > Boot with i915.brightness=0 to disable.
> >
> > KNOWN PROBLEM:
> >  - i915 opregion brightness control silently fails on GM45 (pci-id 0x2a42)
> >
> > [RFC PATCH 1/2] acpi/video: acpi_brightness_hook API
> > [RFC PATCH 2/2] drm/i915: override acpi brightness control
> >
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> >
> 
> Are you sure this is a good idea to enable it by default just because
> of a problem with one manufacturer (Dell)?

This issue is with many manufactures. From this bug you can see HP
machines are effected also.

https://bugs.launchpad.net/ubuntu/+source/alsa-driver/+bug/568611
> 
> My Lenovo laptop has fine brightness control with a GM45 and this may break it.
> Might be safer only to enable it for laptops with known problems.
> 
> 
> Regards,
> Pedro
> --
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