On Fri, Sep 28, 2012 at 12:29:56PM +0100, Chris Wilson wrote: > If we accumulate unpin tasks because we are pageflipping faster than the > system can schedule its workers, we can effectively create a > pin-leak. The solution taken here is to limit the number of unpin tasks > we have per-crtc and to flush those outstanding tasks if we accumulate > too many. This should prevent any jitter in the normal case, and also > prevent the hang if we should run too fast. > > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=46991 > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk> > --- > drivers/gpu/drm/i915/intel_display.c | 20 +++++++++++++++----- > drivers/gpu/drm/i915/intel_drv.h | 4 +++- > 2 files changed, 18 insertions(+), 6 deletions(-) > > diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c > index 04407fd..14f1b51 100644 > --- a/drivers/gpu/drm/i915/intel_display.c > +++ b/drivers/gpu/drm/i915/intel_display.c > @@ -6310,14 +6310,19 @@ static void intel_unpin_work_fn(struct work_struct *__work) > { > struct intel_unpin_work *work = > container_of(__work, struct intel_unpin_work, work); > + struct drm_device *dev = work->crtc->dev; > > - mutex_lock(&work->dev->struct_mutex); > + mutex_lock(&dev->struct_mutex); > intel_unpin_fb_obj(work->old_fb_obj); > drm_gem_object_unreference(&work->pending_flip_obj->base); > drm_gem_object_unreference(&work->old_fb_obj->base); > > - intel_update_fbc(work->dev); > - mutex_unlock(&work->dev->struct_mutex); > + intel_update_fbc(dev); > + mutex_unlock(&dev->struct_mutex); > + > + BUG_ON(atomic_read(&to_intel_crtc(work->crtc)->unpin_work_count) == 0); > + atomic_dec(&to_intel_crtc(work->crtc)->unpin_work_count); AFAICS you always have struct_mutex locked in the relevant functions, so no need for an atomic variable. -- Ville Syrj?l? Intel OTC
