[PATCH 1/9] drm/imx: ipuv3-plane: make sure x/y offsets are even in case of chroma subsampling

[Philipp Zabel]

Am Mittwoch, den 19.10.2016, 15:12 +0800 schrieb Ying Liu:
> On Wed, Oct 19, 2016 at 12:07 AM, Philipp Zabel <p.zabel at pengutronix.de> wrote:
> > Odd x/y offsets are not allowed for chroma subsampled planar YUV
> > formats.
> >
> > Signed-off-by: Philipp Zabel <p.zabel at pengutronix.de>
> > ---
> >  drivers/gpu/drm/imx/ipuv3-plane.c | 8 ++++++++
> >  1 file changed, 8 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/imx/ipuv3-plane.c b/drivers/gpu/drm/imx/ipuv3-plane.c
> > index 5c34299..3a03fd8 100644
> > --- a/drivers/gpu/drm/imx/ipuv3-plane.c
> > +++ b/drivers/gpu/drm/imx/ipuv3-plane.c
> > @@ -259,6 +259,7 @@ static int ipu_plane_atomic_check(struct drm_plane *plane,
> >         struct drm_framebuffer *fb = state->fb;
> >         struct drm_framebuffer *old_fb = old_state->fb;
> >         unsigned long eba, ubo, vbo, old_ubo, old_vbo;
> > +       int hsub, vsub;
> >
> >         /* Ok to disable */
> >         if (!fb)
> > @@ -372,6 +373,13 @@ static int ipu_plane_atomic_check(struct drm_plane *plane,
> >
> >                 if (old_fb && old_fb->pitches[1] != fb->pitches[1])
> >                         crtc_state->mode_changed = true;
> > +
> > +               /* x and y offsets must be even in case of chroma subsampling */
> 
> True for x offsets, but not for y offsets, e.g., NV16.

That should be ok, for NV16 vsub==1, so (y&(vsub-1)) will always be
false. Only for 4:2:0 subsampled formats is vsub==2, and then
(y&(vsub-1)) will only be true if y is odd.
I'll change the comment to:
		/*
		 * The x/y offsets must be even in case of horizontal/vertical
		 * chroma subsampling.
		 */

regards
Philipp