On Tue, 2009-02-17 at 10:34 -0800, Jesse Barnes wrote: > On Tuesday, February 17, 2009 9:43 am Michel Dänzer wrote: > > On Tue, 2009-02-17 at 09:27 -0800, Jesse Barnes wrote: > > > On Tuesday, February 17, 2009 9:04 am Michel Dänzer wrote: > > > > On Mon, 2009-02-16 at 10:42 -0800, Jesse Barnes wrote: > > > > > On Sunday, February 15, 2009 11:33 pm Michel Dänzer wrote: > > > > > > On Fri, 2009-02-13 at 10:27 -0800, Jesse Barnes wrote: > > > > > > > Recall our last discussion where I outlined the cases we'd have > > > > > > > to deal with in the modeset ioctl if we didn't use get/put to > > > > > > > just keep interrupts on around the calls: > > > > > > > > > > > > But we are intending to keep them on around the calls. So the > > > > > > problem is that you are disabling the IRQ in between? Maybe a > > > > > > solution could be not to mess with the counter when > > > > > > disabling/enabling the IRQ. It needs to be guarded by the modeset > > > > > > ioctl anyway, so shouldn't that work? > > > > > > > > > > The current problem isn't a disable between modeset ioctls, it's a > > > > > disable followed by a counter reset of any kind (modeset ioctls or > > > > > not), since the "last" count we track is just done in the disable > > > > > function, not in the modeset ioctl. Doing in in the modeset ioctl > > > > > instead may be possible, but as I said there are lots of cases to > > > > > deal with. > > > > > > > > Isn't the actual problem that drm_irq_uninstall() updates last_vblank? > > > > If it didn't (and the modeset ioctl is properly called around the > > > > disabling and re-enabling of the IRQ), wouldn't it just work? > > > > > > No, this happens w/o an uninstall, it's just due to wraparound being > > > added between the disable timer & the next drm_vblank_get. > > > > I still don't understand the problem then; this can only happen if there > > actually was a wraparound, as the drm_vblank_get must happen (via the > > modeset ioctl) before the hardware frame counter resets for any other > > reason. > > Maybe I'm misunderstanding the problem, lemme walk through the logic: > - we're running along, and at some point the vblank disable timer fires > -> last_vblank = current counter (23252 for example) > - at some later point we do a DPMS or mode set, pre-modeset is called: > - call drm_vblank_get > - enable vblank events > - get current counter (should be >23252 if called correctly) > - diff = cur - last (some small number) > - diff is added > - post mode set > - just put (re-enable the timer) and clear the modeset flag > - another DPMS event comes in before the timer fires > - modeset flag is clear so it goes through the normal path > - call drm_vblank_get > - enable events > - get current counter (will be small this time) > - diff = cur - last (some large number, and cur < last) > - wraparound value + diff is added
The second drm_vblank_get doesn't call drm_update_vblank_counter, as vblank_enabled is still 1. -- Earthling Michel Dänzer | http://www.vmware.com Libre software enthusiast | Debian, X and DRI developer ------------------------------------------------------------------------------ Open Source Business Conference (OSBC), March 24-25, 2009, San Francisco, CA -OSBC tackles the biggest issue in open source: Open Sourcing the Enterprise -Strategies to boost innovation and cut costs with open source participation -Receive a $600 discount off the registration fee with the source code: SFAD http://p.sf.net/sfu/XcvMzF8H -- _______________________________________________ Dri-devel mailing list Dri-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/dri-devel
