On Wed, Jan 04, 2012 at 07:40:45PM +0100, Daniel Vetter wrote: > Two things seem to do the trick on my ivb machine here: > - prevent the gt from powering down while waiting for seqno > notification interrupts by grabbing the force_wake in get_irq (and > dropping it in put_irq again). > - ordering writes from the ring's CS by reading a CS register, ACTHD > seems to work. > > Only the blt&bsd ring on ivb seem to be massively affected by this, > but for paranoia do this dance also on the render ring and on snb > (i.e. all gpus with forcewake). > > Tested with Eric's glCopyPixels loop which without this patch scores a > missed irq every few seconds. > > This patch needs my forcewake rework to use a spinlock instead of > dev->struct_mutex. > > v2: Improve the comment per Eugeni Dodonov's suggestion. > > Cc: stable at kernel.org > Cc: Eric Anholt <eric at anholt.net> > Cc: Kenneth Graunke <kenneth at whitecape.org> > Cc: Eugeni Dodonov <eugeni.dodonov at intel.com> > Tested-by: Eugeni Dodonov <eugeni.dodonov at intel.com> > Reviewed-by: Eugeni Dodonov <eugeni.dodonov at intel.com> > Signed-Off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
