<div class="gmail_quote">On Wed, Nov 2, 2011 at 09:46, Daniel Vetter <<a href="mailto:daniel.vetter@ffwll.ch">daniel.vetter@ffwll.ch</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;"> GPU reset is a very important piece of our infrastructure. Unfortunately we only really test it 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. 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. Signed-Off-by: Daniel Vetter <<a href="mailto:daniel.vetter@ffwll.ch">daniel.vetter@ffwll.ch</a>> </blockquote><div> Reviewed-by: Eugeni Dodonov <<a href="mailto:eugeni.dodonov@intel.com">eugeni.dodonov@intel.com</a>> Could be handy for debugging, I like it. </div></div> -- Eugeni Dodonov<a href="http://eugeni.dodonov.net/" target="_blank"> </a>