[Intel-gfx] [PATCH] drm/i915: Enable GSE interrupt on BDW+

[Aaron Lu]

On 12/04/2015 08:59 PM, Jani Nikula wrote:
> On Fri, 04 Dec 2015, Daniel Vetter <daniel at ffwll.ch> wrote:
>> On Wed, Dec 02, 2015 at 12:17:10AM +0200, ville.syrjala at linux.intel.com wrote:
>>> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
>>>
>>> We've never actually enabled or unmasked the GSE interrupt on BDW+,
>>> even though the interrupt handler was always prepared for it.
>>> Let's enable it and see what happens.
>>>
>>> Credit to Mark Kettenis who fixed this in the OpenBSD fork of the
>>> driver. He reports that it fixed the "ACPI _BCM/_BCQ-based
>>> brightness mechanism on a MacBookPro12,1 and a 3rd gen Lenovo X1
>>> Carbon" for them.

Nice fix, thanks!

>>>
>>> References: http://lists.freedesktop.org/archives/intel-gfx/2015-December/081799.html
>>> Reported-by: Mark Kettenis <mark.kettenis at xs4all.nl>
>>> Cc: Mark Kettenis <mark.kettenis at xs4all.nl>
>>> Cc: Jani Nikula <jani.nikula at linux.intel.com>
>>> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
>>
>> Oh dear, there probably goes all our backlight fun. And how did we miss
>> that DE_MISC wasn't enabled for this long ... but there's indeed nothing
>> else interesting in there. Imo -fixes, and cc: stable as soon as someone
>> confirms it fixes something on our end too.
> 
> I think this hasn't been such a big issue for us because we've mostly
> moved on to native backlight, which is not affected.
> 
> Aaron, do you have any Broadwell ACPI backlight bugs open that might be
> fixed by this?

No, not at this moment. As you have pointed, we should be using the
native interface instead of the ACPI one for those machines.
Thanks for the info :-)

Regards,
Aaron