r277959 breaks X display on IvyBridge mobile GT2 IG

[Adrian Chadd]

On 16 February 2015 at 14:40, Ian FREISLICH <ianf at capeaugusta.com> wrote:
> Ian FREISLICH wrote:
>> Adrian Chadd wrote:
>> > Hi,
>> >
>>
>> > There's a "invert backlight" option in i915, try setting it to 1?
>>
>> This is pretty much all I could find (unless I was looking in the
>> wrong place).  It makes no difference.  The backlight appears to
>> be disabled.
>
> Adrian, do you have any idea how to fix the backlight for my laptop?
> I ended up reversing out your change r277959 in my local copy to
> make the backlight work again here.

Hi,

I don't, no. I haven't dug further into the i915 backlight control
code because, well, a lot of changed in that update. The backlight
code was in a lot of flux during the period of time kib chose to fast
forward, so it's not unsurprising that it broke for some.

I think for now we'll need a quirk that can be added for each laptop
we find with that particular behaviour. The real solution is to
continue sliding i915 forward in time.



-adrian