On Thu, Nov 26, 2015 at 03:49:00PM +0100, Daniel Vetter wrote: > On Thu, Nov 26, 2015 at 01:31:42PM +0000, Chris Wilson wrote: > > We have relied upon the sole caller (wait_ioctl) validating the timeout > > argument. However, when waiting for multiple requests I forgot to ensure > > that the timeout was still positive on the later requests. This is more > > simply done inside __i915_wait_request. > > > > Fixes regression introduced in > > commit b47161858ba13c9c7e03333132230d66e008dd55 > > Author: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > > Date: Mon Apr 27 13:41:17 2015 +0100 > > > > drm/i915: Implement inter-engine read-read optimisations > > > > Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > > Cc: Lionel Landwerlin <lionel.g.landwerlin@xxxxxxxxxxxxxxx> > > Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx> > > Cc: Daniel Vetter <daniel.vetter@xxxxxxxx> > > Cc: stable@xxxxxxxxxxxxxxx > > Commit message should explain what the actual problem is - we add 1 jiffy > of delay for each wait_request, potentially waiting quite a bit longer > than what userspace asked for. > > And not sure this really justifies for cc: stable, since all the wait > syscalls reserve the right to wait longer. Of course we should fix it, > just to keep validating this possible. Dropping stable is fine, that was just a knee jerk reaction to finding a regression. The impact is 1 jiffie for each extra active ring for a wait_ioctl with a timeout -- I don't think anyone has noticed. -Chris -- Chris Wilson, Intel Open Source Technology Centre -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html