On Tue, Sep 22, 2015 at 10:06:47AM +0100, Tvrtko Ursulin wrote: > > On 08/26/2015 10:26 AM, Daniel Vetter wrote: > >On Sun, Aug 23, 2015 at 05:52:47PM +0530, Sagar Arun Kamble wrote: > >>On BXT, We Observe timeout for forcewake request completion with 2ms > >>polling period as given here: > >>[drm:fw_domains_get] ERROR render: timed out waiting for forcewake ack > >>request. > >>Polling for 50ms is recommended to avoid these timeouts. > >> > >>Change-Id: Ie715b0069a3049606e9602bc5e97a6511890864d > >>Signed-off-by: Sagar Arun Kamble <sagar.a.kam...@intel.com> > > > >Probably needs cc: stable plus a pile of bugzilla links all over ... > > If the required wait is typically that long, shouldn't we be worried > about busy polling?
With an exponential backoff (i.e. busyspin for the first ~jiffie/1ms) then usleep_range 1, 2, 4, 8,..? And also keeping the fw wakelock for longer than a jiffie to optimistically avoid these multi-jiffie stalls. Whilst grumbling. -Chris -- Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/intel-gfx
