[Intel-gfx] [PATCH v2] drm/i915: Check for timeout completion when waiting for the rq to submitted

[Chris Wilson]

On Thu, Feb 09, 2017 at 09:10:12AM +0000, Tvrtko Ursulin wrote:
> 
> On 08/02/2017 18:12, Chris Wilson wrote:
> >We first wait for a request to be submitted to hw and assigned a seqno,
> >before we can wait for the hw to signal completion (otherwise we don't
> >know the hw id we need to wait upon). Whilst waiting for the request to
> >be submitted, we may exceed the user's timeout and need to propagate the
> >error back.
> >
> >v2: Make ETIME into an error from wait_for_execute for consistent exit
> >handling.
> >
> >Reported-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> >Fixes: 4680816be336 ("drm/i915: Wait first for submission, before waiting for request completion")
> >Testcase: igt/gem_wait/basic-await
> >Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> >Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> >Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
> >Cc: <drm-intel-fixes at lists.freedesktop.org> # v4.10-rc1+
> >---
> > drivers/gpu/drm/i915/i915_gem_request.c | 7 ++++++-
> > 1 file changed, 6 insertions(+), 1 deletion(-)
> >
> >diff --git a/drivers/gpu/drm/i915/i915_gem_request.c b/drivers/gpu/drm/i915/i915_gem_request.c
> >index 72b7f7d9461d..f31deeb72703 100644
> >--- a/drivers/gpu/drm/i915/i915_gem_request.c
> >+++ b/drivers/gpu/drm/i915/i915_gem_request.c
> >@@ -1025,8 +1025,13 @@ __i915_request_wait_for_execute(struct drm_i915_gem_request *request,
> > 			break;
> > 		}
> >
> >+		if (!timeout) {
> >+			timeout = -ETIME;
> >+			break;
> >+		}
> >+
> > 		timeout = io_schedule_timeout(timeout);
> >-	} while (timeout);
> >+	} while (1);
> > 	finish_wait(&request->execute.wait, &wait);
> >
> > 	if (flags & I915_WAIT_LOCKED)
> >
> 
> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>

Thanks for catching it. Hopefully the window it exists in 4.10 is short
enough that we aren't deluged with bug reports...
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre