On Thu, May 03, 2012 at 04:00:00PM -0300, Eugeni Dodonov wrote: > On Thu, May 3, 2012 at 9:48 AM, Daniel Vetter <daniel.vetter at ffwll.ch>wrote: > > > gpu reset is a very important piece of our infrastructure. > > Unfortunately we only really it test by actually hanging the gpu, > > which often has bad side-effects for the entire system. And the gpu > > hang handling code is one of the rather complicated pieces of code we > > have, consisting of > > - hang detection > > - error capture > > - actual gpu reset > > - reset of all the gem bookkeeping > > - reinitialition of the entire gpu > > > > This patch adds a debugfs to selectively stopping rings by ceasing to > > update the hw tail pointer, which will result in the gpu no longer > > updating it's head pointer and eventually to the hangcheck firing. > > This way we can exercise the gpu hang code under controlled conditions > > without a dying gpu taking down the entire systems. > > > > Patch motivated by me forgetting to properly reinitialize ppgtt after > > a gpu reset. > > > > Usage: > > > > echo $((1 << $ringnum)) > i915_ring_stop # stops one ring > > > > echo 0xffffffff > i915_ring_stop # stops all, future-proof version > > > > then run whatever testload is desired. i915_ring_stop automatically > > resets after a gpu hang is detected to avoid hanging the gpu to fast > > and declaring it wedged. > > > > v2: Incorporate feedback from Chris Wilson. > > > > v3: Add the missing cleanup. > > > > v4: Fix up inconsistent size of ring_stop_read vs _write, noticed by > > Eugeni Dodonov. > > > > Signed-Off-by: Daniel Vetter <daniel.vetter at ffwll.ch> > > Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk> > > > > Reviewed-by: Eugeni Dodonov <eugeni.dodonov at intel.com> I've slurped the hangman into -next, thanks for the review. -Daniel -- Daniel Vetter Mail: daniel at ffwll.ch Mobile: +41 (0)79 365 57 48
