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

[Thomas Hellstrom]

On 11/21/2014 03:14 PM, Chris Wilson wrote:
> 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
>

So when you say relied upon by user-space, do you mean generic
user-space or driver-specific user-space?

With that, I mean what component is responsible for deciding that the
dumb buffer can be accelerated? The Intel xorg driver?

/Thomas