[PATCH] drm/gem: Warn on illegal use of the dumb buffer interface v2

[Chris Wilson]

On Thu, Nov 20, 2014 at 09:56:25AM +0100, Thomas Hellstrom wrote:
> It happens on occasion that developers of generic user-space applications
> abuse the dumb buffer API to get hold of drm buffers that they can both
> mmap() and use for GPU acceleration, using the assumptions that dumb buffers
> and buffers available for GPU are
> a) The same type and can be aribtrarily type-casted.
> b) fully coherent.

Both (a) and (b) are true for intel and it turns out to be a requirement
for smooth transitions from the boot splash screens into X, and relied
upon by userspace.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre