[Intel-gfx] [PATCH 1/2] drm/i915: remove DRM_AUTH from IOCTLs which also have DRM_RENDER_ALLOW

[Emil Velikov]

On 2019/04/17, Emil Velikov wrote:
> On 2019/04/17, Christian König wrote:
> > This is to work around problems with libva and vainfo.
> > 
> This part reverts a commit from 2013. Something I would wager that will cause
> multiple problems across the board.
> 
> If we look at the intel libva driver in particular, as-is this will cause all
> get param queries on the render node to fail. Something that used to work
> since render node support was introduced.
> 
> Analogously this will break the Intel Mesa driver when using the render node
> and issuing the ioctls.
> 
Silly moment of mine - I've misread which piece gets reverted.
Pardon for the noise.

Personally I would use something like the following, which helps the reader
understand what's happening.


At the moment the following ioctls are exposed by both primary and render
nodes. Yet there's no code-flow difference based on the originating node type.
Thus in reality the exact same code is executed without the "authentication".

So let's drop the DRM_AUTH annotation.

In practise this fixes cases like (but not limited to) libva where the primary
node is opened, yet authentication is lacking prior to issuing the ioctl.

I915_GETPARAM
I915_GEM_EXECBUFFER2_WR
I915_GEM_BUSY
I915_GEM_THROTTLE
I915_GEM_WAIT

HTH
Emil