On Wednesday, February 13, 2008 2:22 pm Stephane Marchesin wrote: > On 2/13/08, Dave Airlie <[EMAIL PROTECTED]> 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... > > Hi, > > 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. > > 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.
IIRC, the reason we came up with this was to deal with CRTC<->output mapping, not for BO permissions so much (doing proper perms there still requires a lot of work). You don't want any application to be able to change CRTC<->output mappings, or bind BOs to CRTCs. Ideally you'd just have one app that could do that on a given system, and it would contain the distribution's policy regarding output cloning, hotplug actions, etc. So the master/slave concept is really more analogous to pty master & slave nodes than it is to your /dev/sda_ext3 example. You open the master node, ask for a specific mapping, and if you have permission, a slave node will be created that you can do what you like with... Jesse ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ -- _______________________________________________ Dri-devel mailing list Dri-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/dri-devel
