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
