[Intel-gfx] [PATCH 06/12] drm/i915: Add the missing Y/Yf modifiers for SKL+ sprites

[Daniel Stone]

Hi,

On 25 August 2017 at 12:34, Ville Syrjälä <ville.syrjala at linux.intel.com> wrote:
> On Fri, Aug 25, 2017 at 10:40:28AM +0100, Daniel Stone wrote:
>> On 24 August 2017 at 20:10,  <ville.syrjala at linux.intel.com> wrote:
>> > Y/Yf somehow dropped out from the SKL+ sprite modifier list. Add them
>> > in.
>>
>> There's no 'somehow':
>> https://lists.freedesktop.org/archives/intel-gfx/2017-August/134932.html
>>
>> I would prefer to not see this pushed whilst it doesn't actually work.
>
> Works fine here. Well, I should say it works just as well as it does for
> the primary plane. There are no plane specific checks in the wm/ddb code
> IIRC so if something is broken for sprites then it's most likely equally
> broken for the primary plane.

How did you test it?

The failure mode I observed was that the primary plane had a giant
allocation, having previously had plain Y-tiling or Y-CCS enabled.
After switching the primary to linear or X-tiled, trying to configure
a 256x256 sprite plane with either Y-tiled or CCS failed, as it only
had a DDB allocation of 31 blocks, where it needed 33. So it's not
that there are plane-specific checks rejecting anything, it's that the
allocations never got drawn up to give the sprite plane enough room to
do anything other than X-tiled.

I saw this on both SKL (3200x1800 or 2560x1440) and APL (1920x1080).

Cheers,
Daniel