[PATCH 1/1] drm: i915: don't use OpRegion for XPS 13 IvyBridge

[Jani Nikula]

On Mon, 29 Aug 2016, Andrea Arcangeli <aarcange at redhat.com> wrote:
> On Mon, Aug 29, 2016 at 10:24:38AM +0300, Jani Nikula wrote:
>> If it's an Iybridge, there's no low vswing, and that explanation is
>> false. You can verify by trying i915.edp_vswing=1 or i915.edp_vswing=2
>> on an unpatched kernel.
>
> What I should look for when trying those two settings? Will they
> successfully fix my problem with intel_backlight with upstream 4.8-rc?
>
> I thought it had to be the same issue as on skylake as I get the
> backlight flikering at low frequency but getting brighter and darker
> in a cycle lasting a few seconds and I thought there couldn't be too
> many other random bugs that ends up with the same side effect.

Your Ivybridge does not have low voltage swing *and* low voltage swing
has nothing to do with the backlight. The regressing commit may be the
same for you, but the failure mode appears to be completely different.

BR,
Jani.




-- 
Jani Nikula, Intel Open Source Technology Center