[Intel-gfx] [PATCH] drm/i915: Adding dbuf support for skl nv12 format.

[Konduru, Chandra]

> -----Original Message-----
> From: Daniel Vetter [mailto:daniel.vetter at ffwll.ch] On Behalf Of Daniel Vetter
> Sent: Monday, May 04, 2015 8:01 AM
> To: Konduru, Chandra
> Cc: intel-gfx at lists.freedesktop.org; Vetter, Daniel; Syrjala, Ville
> Subject: Re: [Intel-gfx] [PATCH] drm/i915: Adding dbuf support for skl nv12
> format.
> 
> On Mon, Apr 27, 2015 at 03:47:37PM -0700, Chandra Konduru wrote:
> > Skylake nv12 format requires dbuf (aka. ddb) calculations and
> > programming for each of y and uv sub-planes. Made minor changes to
> > reuse current dbuf calculations and programming for uv plane. i.e.,
> > with this change, existing computation is used for either packed
> > format or uv portion of nv12 depending on incoming format. Added new
> > code for dbuf computation and programming for y plane.
> >
> > This patch is a pre-requisite for adding NV12 format support.
> > Actual nv12 support is coming in later patches.
> >
> > Signed-off-by: Chandra Konduru <chandra.konduru at intel.com>
> 
> Just aside (and not a blocker for this patch really). Do we have nv12 subtest in all
> the relevant plane tests (rotation, scaling, ...) to exercise this code? Not sure
> whether we can redo the yuv->rgb conversion correctly in software to match
> hw, might need to pick special colors that convert accurately.
> 
> Anyway given how often we've broken the sprite code I really think we need full
> functional tests (i.e. including crc checks).

I have written an i-g-t test kms_nv12 to test/exercise this patch and 
subsequent NV12 patch series which was submitted last week after
this patch. It tests nv12 along with rotation, scaling and does
some crc checks. 
But because chrome upsampling is done using scaler which uses multiple taps,
crcs aren't going to match with original reference flip with RGB format. I tried with 
simple solid color. Can you please take a look that?

> -Daniel
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch