On Mon, 17 Aug 2009 22:22:34 +0200 Thomas Hellström <tho...@shipmail.org> wrote:
> Kristian Høgsberg wrote: > > This patch adds a vblank synced pageflip ioctl for to the > > modesetting family of ioctls. The ioctl takes a crtc and an fb and > > schedules a pageflip to the new fb at the next coming vertical > > blank event. This feature lets userspace implement tear-free > > updating of the screen contents with hw-guaranteed low latency page > > flipping. > > > > The ioctl is asynchronous in that it returns immediately and then > > later notifies the client by making an event available for reading > > on the drm fd. This lets applications add the drm fd to their main > > loop and handle other tasks while waiting for the flip to happen. > > The event includes the time of the flip, the frame counter and a 64 > > bit opaque token provided by user space in the ioctl. > > > > Based on work and suggestions from > > Jesse Barnes <jbar...@virtuousgeek.org>, > > Jakob Bornecrantz <wallbra...@gmail.com>, > > Chris Wilson <ch...@chris-wilson.co.uk> > > > > Signed-off-by: Kristian Høgsberg <k...@redhat.com> > > Signed-off-by: Jesse Barnes <jbar...@virtuousgeek.org> > > --- > > > > Ok, another version of this patch. This one has fixes to work with > > radeon kms plus a missing list head init that would cause an oops > > in the case where we schedule a flip before the previous one has > > been queued. > > > > I'm now ready to propose this patch for the 2.6.32 merge window. > > > > > Hi! > First a general question: There is some hardware (for example > Unichromes and Chrome9) that can schedule > page-flips in the command stream after optional vblank barriers. For > this kind of hardware the pageflip would be a matter of scheduling > the flip and fence the old and new buffers. No need for delayed > unpins and explicit user-space notifications, although the workqueue > could be handy to avoid command processing stalls in the vblank > barriers. How would such a scheme fit into the framework below? If you fence the flip, doesn't that mean you only unpin after it's completed? The initial version of this patch used a command stream flip, but I still had to worry about pinning... If you don't need the userspace notifications we could probably factor that out; do you see any issues with the flip ioctl itself? If not, we can change things as needed if/when more drivers support it... > A couple of years ago, any attempt to return anything else than 0 > from drm poll resulted in an X server error. > http://freedesktop.org/bugzilla/show_bug.cgi?id=1505. The fix > mentioned in the bug was actually to return 0 from drm poll, and a > comment about this is still present in drm.git. The above breaks drm > for old X servers and all drivers, which I think is against drm > policy? Ouch... I remember Kristian had some issues with this part, but I don't think this was one of them. -- Jesse Barnes, Intel Open Source Technology Center ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july -- _______________________________________________ Dri-devel mailing list Dri-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/dri-devel
