On Wed, Feb 13, 2008 at 5:22 PM, Stephane Marchesin
> On 2/13/08, Dave Airlie <airlied@...> wrote:
> > So I've been thinking about this stuff a lot lately wrt to getting the
> > DRM into a state that enables fast-user-switching, GPGPU apps,
> > different users on a per head one a single card..
> > http://dri.freedesktop.org/wiki/DRMRedesign
> > has a nice picture and some notes.. either comment direct on the webpage,
> > or reply here..
> > A lot of the code heading in this direction just got merged into
> > modesetting-101, it should in theory all be backwards compat in the single
> > render/master case...
> So basically, you'd expose multiple /dev entries for a single piece of
> hardware. As I said on irc, this would be like exposing /dev/sda1_ext2
> and /dev/sda1_xfs and ... which obviously doesn't scale long-term.
Let me remind you that /dev/sda1 and /dev/sda2 are just that -
multiple dev entries for /dev/sda. The /dev/sdaX files represent the
different partitions on /dev/sda not different pieces of hardware.
> Lets forget about the concept of "master" for a moment. In a case
> where the concept of "master" does not exist, an application that can
> draw to screen (formerly "master") would simply be one that has a
> scanout BO and is using it.
> So here is the point: with the current work on enforcing proper
> permissions on BOs (including scanout BOs), is a separate device
> really needed ? The reason for doing this device separation in the
> first place basically comes down to enforcing those permissions
> properly in a per-app fashion. The same effect could be achieved by
> enforcing the policy on BO creation instead of device opening.
The nice thing about using the device model is that it's an
established mechanism, that's already implemented and currently used
for many other devices. I would prefer not to invent a new