NAK: [PULL Wily] drm/i915: Add workarounds for SKL

[Timo Aaltonen]

On 21.08.2015 05:32, Timo Aaltonen wrote:
> On 20.08.2015 23:28, Jason Gerard DeRose wrote:
>>
>>
>> On Thu, Aug 20, 2015 at 1:15 PM, Tim Gardner <tim.gardner at canonical.com>
>> wrote:
>>> On 08/20/2015 01:06 PM, Timo Aaltonen wrote:
>>>> On 20.08.2015 22:03, Tim Gardner wrote:
>>>>> On 08/20/2015 04:36 AM, Timo Aaltonen wrote:
>>>>>> git://kernel.ubuntu.com/tjaalton/ubuntu-wily.git skl
>>>>>
>>>>> I'm not too keen on the content of these commit messages. All say
>>>>> "cherry picked", but I'm not finding any of them in Linus' repository.
>>>>
>>>> That's because Linus' tree still has only 4.2, these are from
>>>> drm-intel-next.
>>>>
>>>> If you prefer waiting once 4.3-rc1 is released that's fine. Or I can
>>>> send another pull request with SAUCE and "backported from.." on the
>>>> commits.
>>>>
>>>>
>>>>
>>>
>>> I would prefer waiting until they have been merged upstream.
>>
>> For what it's worth, there are huge Skylake GPU regressions currently in
>> Wily compared to Vivid and Trusty (with Vivid HWE).  Bad enough that
>> it's almost impossible to test desktop Wily on Skylake hardware as Unity
>> is basically unusable.
>>
>> At a glance, these patches might be the needed fixes, and if they are,
>> from my perspective it would be nice to have them merged into Wily
>> sooner rather than later just for testing purposes.
>>
>> Which doesn't mean merging them now is the right thing to do, of course.
>> Just my two cents :D
> 
> Sounds like you need i915.preliminary_hw_support=1 at least..

..because starting from wily the config option is no longer on by
default, as it might make the installer unusable on new HW. For testing
purposes it's easy to add that option to /etc/default/grub and run
update-grub.

SKL is working mostly fine on Wily if you don't stress it too much.
These WA's will help with stability, eventually.


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t