<html> <head> <base href="https://bugs.freedesktop.org/"> </head> <body> <div> <a class="bz_bug_link bz_status_RESOLVED bz_closed" title="RESOLVED FIXED - missed hangcheck wakeup" href="https://bugs.freedesktop.org/show_bug.cgi?id=104840#c4">Comment # 4</a> on <a class="bz_bug_link bz_status_RESOLVED bz_closed" title="RESOLVED FIXED - missed hangcheck wakeup" href="https://bugs.freedesktop.org/show_bug.cgi?id=104840">bug 104840</a> from <a class="email" href="mailto:chris@chris-wilson.co.uk" title="Chris Wilson <chris@chris-wilson.co.uk>"> Chris Wilson</a> <pre>commit 889230489b6b138ba97ba2f13fc9644a3d16d0d2 Author: Chris Wilson <<a href="mailto:chris@chris-wilson.co.uk">chris@chris-wilson.co.uk</a>> Date: Mon Jan 29 14:41:04 2018 +0000 drm/i915: Always run hangcheck while the GPU is busy Previously, we relied on only running the hangcheck while somebody was waiting on the GPU, in order to minimise the amount of time hangcheck had to run. (If nobody was watching the GPU, nobody would notice if the GPU wasn't responding -- eventually somebody would care and so kick hangcheck into action.) However, this falls apart from around commit 4680816be336 ("drm/i915: Wait first for submission, before waiting for request completion"), as not all waiters declare themselves to hangcheck and so we could switch off hangcheck and miss GPU hangs even when waiting under the struct_mutex. If we enable hangcheck from the first request submission, and let it run until the GPU is idle again, we forgo all the complexity involved with only enabling around waiters. We just have to remember to be careful that we do not declare a GPU hang when idly waiting for the next request to be come ready, as we will run hangcheck continuously even when the engines are stalled waiting for external events. This should be true already as we should only be tracking requests submitted to hardware for execution as an indicator that the engine is busy. Fixes: 4680816be336 ("drm/i915: Wait first for submission, before waiting for request completion" Bugzilla: <a class="bz_bug_link bz_status_RESOLVED bz_closed" title="RESOLVED FIXED - missed hangcheck wakeup" href="show_bug.cgi?id=104840">https://bugs.freedesktop.org/show_bug.cgi?id=104840</a> Signed-off-by: Chris Wilson <<a href="mailto:chris@chris-wilson.co.uk">chris@chris-wilson.co.uk</a>> Cc: Chris Wilson <<a href="mailto:chris@chris-wilson.co.uk">chris@chris-wilson.co.uk</a>> Cc: Mika Kuoppala <<a href="mailto:mika.kuoppala@linux.intel.com">mika.kuoppala@linux.intel.com</a>> Link: <a href="https://patchwork.freedesktop.org/patch/msgid/20180129144104.3921-1-chris@chris-wilson.co.uk">https://patchwork.freedesktop.org/patch/msgid/20180129144104.3921-1-chris@chris-wilson.co.uk</a> Reviewed-by: Mika Kuoppala <<a href="mailto:mika.kuoppala@linux.intel.com">mika.kuoppala@linux.intel.com</a>></pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the assignee for the bug.</li> <li>You are on the CC list for the bug.</li> <li>You are the QA Contact for the bug.</li> </ul> </body> </html>