[Intel-gfx] [PATCH 15/15] drm/i915: Add NV12 support to intel_framebuffer_init

[Maarten Lankhorst]

Op 20-01-18 om 22:45 schreef Vidya Srinivas:
> From: Chandra Konduru <chandra.konduru at intel.com>
>
> This patch adds NV12 as supported format
> to intel_framebuffer_init and performs various checks.
>
> v2:
> -Fix an issue in checks added (Chandra Konduru)
>
> v3: rebased (me)
>
> v4: Review comments by Ville addressed
> Added platform check for NV12 in intel_framebuffer_init
> Removed offset checks for NV12 case
>
> v5: Addressed review comments by Clinton A Taylor
> This NV12 support only correctly works on SKL.
> Plane color space conversion is different on GLK and later platforms
> causing the colors to display incorrectly.
> Ville's plane color space property patch series
> in review will fix this issue.
> - Restricted the NV12 case in intel_framebuffer_init to
> SKL and BXT only.
>
> v6: Rebased (me)
>
> v7: Addressed review comments by Ville
> Restricting the NV12 to BXT for now.
>
> v8: Rebased (me)
> Restricting the NV12 changes to BXT and KBL for now.
>
> v9: Rebased (me)
Hey,

Has NV12 been tested at all on skylake with rotation?

y_min_scanlines = 16 for 90°/270° rotation with cpp=1
skl_needs_memory_bw_wa() doubles the scanlines required,
which will trigger the following error quite easily when patching kms_rotation_crc to use NV12:

[   67.049190] [drm:skl_compute_wm_levels [i915]] Requested display configuration exceeds system watermark limitations
[   67.049212] [drm:skl_compute_wm_levels [i915]] [PLANE:28:plane 1A] blocks required = 161/572, lines required = 32/31

If we violate the spec for the workaround, by using 31 lines instead of 32 for 90/270
rotation, the tests work but this needs to be solved first before we can move forward.

~Maarten