VK_EXT_aquire_xlib_display and kernel security concerns

[Andy Ritger]

On Mon, Oct 16, 2017 at 02:17:27PM -0700, Keith Packard wrote:
> 
> Dave Airlie <airlied at gmail.com> writes:
> 
> > If they use acquire extensions they get display enumeration, the
> > problem is display enumeration before the acquire would need special
> > permission elevation.
> 
> And the problem here is that the nVidia driver hides the HMD displays
> from X, forcing the application to use Vulkan enumeration to find the
> VkDisplayKHR to pass to AcquireXlibDisplay...

If the NVIDIA X driver finds an HMD display, it:

(a) Marks it as disconnected.
(b) Does not make its EDID available to RandR clients.

So, unless I'm mistaken, RandR clients will see the HMD as an RandR
output.  But, perhaps the problem is that the RandR client cannot tell
that the output is an HMD, since the EDID is not available?

Item (b) was only an artifact of how the code is structured, not an
intentional decision.  To be fair, disconnected output with EDID sounds
like a slightly odd state.

Anyway, we can update the NVIDIA driver behavior to match whatever
consensus we reach here.

- Andy

> -- 
> -keith
> 

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