[Intel-gfx] [PATCH 0/3] drm/i915: Fix SKL+ 90/270 degree rotated scanout

[Maarten Lankhorst]

Hey,

Op 06-06-17 om 10:29 schreef Tvrtko Ursulin:
>
> On 06/06/2017 09:06, Maarten Lankhorst wrote:
>> Op 05-04-17 om 15:49 schreef Ville Syrjälä:
>>> On Fri, Mar 31, 2017 at 10:23:18PM +0100, Chris Wilson wrote:
>>>> On Fri, Mar 31, 2017 at 09:00:53PM +0300, ville.syrjala at linux.intel.com wrote:
>>>>> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
>>>>>
>>>>> I figured it's about time I fix what I broke with my fb offset stuff.
>>>>> I've posted the scaler thing before, but the watermark and fbc stuff
>>>>> is new.
>>>>>
>>>>> Based on some quick tests the WM fixes seem effective. Or at least
>>>>> underruns seemed to disappear when I was running xonotic with 90/270
>>>>> degree rotation.
>>>> The key question for me is would we be able to detect any of the errors
>>>> in igt? How can we improve our testing?
>>> The rotation test definitely would need some love. It fails to detect
>>> these problems because it scans out a square image. Making it non-square
>>> would at least catch the use of the scaler when it shouldn't be used.
>>>
>>> Detecting the watermark breakage is less clear. I suppose making the
>>> plane have a very wide or very tall aspect ratio might help induce
>>> underruns with the broken wm code.
>>>
>>> Another thing that may or may not be missing from the test is panning.
>>> I'd also like to test scaling, but sadly our hardware makes that
>>> rather hard by not allowing us to force nearest and/or linear filtering,
>>> and bspec doesn't actually document what kind of algorithm the hardware
>>> uses for the different filter modes.
>>>
>> Agreed, the whole series is useful but until we have some tests we may as well not commit it. Nothing prevents it from being broken again in the next commit. :(
>
> In case tests hit a stumbling blocks/delays, I would appreciate if this got reviewed and merged soonish. As it stands I've been applying (and occasionally forgetting to apply) patches locally since September.
>
> And FWIW I would report if it got re-broken, since I'm using monitors in portrait, and like to run recent drm-tip to help catch issues missed elsewhere.
>
>> I'll take a look and see if I can make kms_rotation_crc break without this test.
>
> Would also need to upgrade the test to basic, or count on extended runs getting attention soon? 
Maybe?

I've pushed the fixed test. Managed to test that the scaler is enabled incorrectly and the WM underruns.

Reviewed-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>