On Thu, Apr 17, 2014 at 04:43:17PM +0200, Thierry Reding wrote: > On Fri, Apr 11, 2014 at 11:36:02PM +0200, Daniel Vetter wrote: > > The dev->struct_mutex locking in drm_irq.c only protects > > dev->irq_enabled. Which isn't really much at all and only prevents > > especially nasty ums userspace from concurrently installing the > > interrupt handling a few times. Or at least trying. > > > > There are tons of unlocked readers of dev->irqs_enabled in the vblank > > wait code (and by extension also in the pageflip code since that uses > > the same vblank timestamp engine). > > > > Real modesetting drivers should ensure that nothing can go haywire > > with a sane setup teardown sequence. So we only really need this for > > the drm_control ioctl, everywhere else this will just paper over > > nastiness. > > > > Note that drm/i915 is a bit specially due to the gem+ums combination. > > So there we also need to properly protect the entervt and leavevt > > ioctls. But it's definitely saner to do everything in one go than to > > drop the lock in-between. > > > > Finally there's the gpu reset code in drm/i915. That one's just race > > (concurrent userspace calls to for vblank waits of pageflips could > > spuriously fail). So wrap it up in with a nice comment since fixing > > this is more involved. > > > > Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxx> > > --- > > drivers/gpu/drm/drm_irq.c | 30 +++++++++++++----------------- > > drivers/gpu/drm/i915/i915_drv.c | 5 +++++ > > drivers/gpu/drm/i915/i915_gem.c | 5 +++-- > > 3 files changed, 21 insertions(+), 19 deletions(-) > > Looks good to me: > > Reviewed-by: Thierry Reding <treding@xxxxxxxxxx> Oh, perhaps s/unistall/uninstall/ in the commit subject. Thierry
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