[Intel-gfx] [PATCH 1/2] drm/i915: Don't clobber the addfb2 ioctl params

[Chris Wilson]

On Wed, Nov 11, 2015 at 07:24:40PM +0200, Ville Syrjälä wrote:
> On Wed, Nov 11, 2015 at 05:20:10PM +0000, Chris Wilson wrote:
> > On Wed, Nov 11, 2015 at 07:11:28PM +0200, ville.syrjala at linux.intel.com wrote:
> > > From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > > 
> > > We try to convert the old way of of specifying fb tiling (obj->tiling)
> > > into the new fb modifiers. We store the result in the passed in mode_cmd
> > > structure. But that structure comes directly from the addfb2 ioctl, and
> > > gets copied back out to userspace, which means we're clobbering the
> > > modifiers that the user provided (all 0 since the DRM_MODE_FB_MODIFIERS
> > > flag wasn't even set by the user). Hence if the user reuses the struct
> > > for another addfb2, the ioctl will be rejected since it's now asking for
> > > some modifiers w/o the flag set.
> > 
> > What do we actually pass back to userspace through the struct?
> 
> The fb id.

D'oh. Time to step away from the computer...
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre