Re: [PATCH] drm/i915: Error out when trying to set a y-tiled as a sprite

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Sun, Oct 28, 2012 at 10:04:54AM +0000, Chris Wilson wrote:
> On Fri, 26 Oct 2012 10:42:54 -0700, Jesse Barnes <jbarnes@virtuousgeek.org> wrote:
> > On Fri, 26 Oct 2012 18:30:50 +0100
> > Damien Lespiau <damien.lespiau@gmail.com> wrote:
> > 
> > > From: Damien Lespiau <damien.lespiau@intel.com>
> > > 
> > > Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
> > > ---
> > >  drivers/gpu/drm/i915/intel_sprite.c | 5 +++++
> > >  1 file changed, 5 insertions(+)
> > > 
> > > diff --git a/drivers/gpu/drm/i915/intel_sprite.c b/drivers/gpu/drm/i915/intel_sprite.c
> > > index 3434b6e..aa8d09b 100644
> > > --- a/drivers/gpu/drm/i915/intel_sprite.c
> > > +++ b/drivers/gpu/drm/i915/intel_sprite.c
> > > @@ -465,6 +465,11 @@ intel_update_plane(struct drm_plane *plane, struct drm_crtc *crtc,
> > >  	if (intel_plane->pipe != intel_crtc->pipe)
> > >  		return -EINVAL;
> > >  
> > > +	/* Sprite planes can be linear or x-tiled surfaces */
> > > +	if (!(obj->tiling_mode == I915_TILING_NONE ||
> > > +	      obj->tiling_mode == I915_TILING_X))
> > > +		return -EINVAL;
> > > +
> > >  	/*
> > >  	 * Clamp the width & height into the visible area.  Note we don't
> > >  	 * try to scale the source if part of the visible region is offscreen.
> > 
> > Do we not catch this when we make the fb?  If not we may want to do
> > this there...
> 
> We do. However, we don't catch userspace changing the tiling on an
> existing fb (unless actually pinned)...

Why not simply count how many fbs reference a given bo, and reject
tiling changes when the count > 0?

-- 
Ville Syrjälä
Intel OTC