[PATCH 3/3] drm/imx: ipuv3-plane: Access old u/vbo properly in ->atomic_check for YU12/YV12

[Philipp Zabel]

Hi Liu,

Am Montag, den 10.10.2016, 14:50 +0800 schrieb Liu Ying:
> Before accessing the u/v offset(aka, u/vbo for IPUv3) of the old plane state's
> relevant fb, we should make sure the fb is in YU12 or YV12 pixel format(which
> are the two YUV pixel formats we support only), otherwise, we are likely to
> trigger BUG_ON() in drm_plane_state_to_u/vbo() since the fb's pixel format is
> probably not YU12 or YV12.
> 
> Link: https://bugs.freedesktop.org/show_bug.cgi?id=98150
> Fixes: c6c1f9bc798b ("drm/imx: Add active plane reconfiguration support")
> Cc: stable at vger.kernel.org # 4.8
> Signed-off-by: Liu Ying <gnuiyl at gmail.com>
> ---
>  drivers/gpu/drm/imx/ipuv3-plane.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/imx/ipuv3-plane.c b/drivers/gpu/drm/imx/ipuv3-plane.c
> index e33110e..a691892 100644
> --- a/drivers/gpu/drm/imx/ipuv3-plane.c
> +++ b/drivers/gpu/drm/imx/ipuv3-plane.c
> @@ -359,7 +359,7 @@ static int ipu_plane_atomic_check(struct drm_plane *plane,
>  		if ((ubo > 0xfffff8) || (vbo > 0xfffff8))
>  			return -EINVAL;
>  
> -		if (old_fb) {
> +		if (old_fb && old_fb->pixel_format == fb->pixel_format) {
>  			old_ubo = drm_plane_state_to_ubo(old_state);
>  			old_vbo = drm_plane_state_to_vbo(old_state);
>  			if (ubo != old_ubo || vbo != old_vbo)

thank you for the patches. I have applied patches 1 and 2, but with this
change UBO/VBO changes are ignored when switching from YU12 to YV12.

Shouldn't we rather set crtc_state->mode_changed = true if either
(fb->pixel_format != old_fb->pixel_format) for any pixel format or
(ubo != old_ubo || vbo != old_vbo) for YUV formats, instead of returning
-EINVAL?

regards
Philipp