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

[Chris Wilson]

On Wed, Feb 08, 2017 at 05:28:39PM +0000, Tvrtko Ursulin wrote:
> 
> On 08/02/2017 16:54, 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.
> >
> >Reported-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> >Fixes: 4680816be336 ("drm/i915: Wait first for submission, before waiting for request completion")
> >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 | 3 +++
> > 1 file changed, 3 insertions(+)
> >
> >diff --git a/drivers/gpu/drm/i915/i915_gem_request.c b/drivers/gpu/drm/i915/i915_gem_request.c
> >index 72b7f7d9461d..69aff559cf8e 100644
> >--- a/drivers/gpu/drm/i915/i915_gem_request.c
> >+++ b/drivers/gpu/drm/i915/i915_gem_request.c
> >@@ -1084,6 +1084,9 @@ long i915_wait_request(struct drm_i915_gem_request *req,
> > 		if (timeout < 0)
> > 			goto complete;
> >
> >+		if (!timeout)
> >+			return -ETIME;
> >+
> > 		GEM_BUG_ON(!i915_sw_fence_done(&req->execute));
> > 	}
> > 	GEM_BUG_ON(!i915_sw_fence_done(&req->submit));
> >
> 
> Perhaps "else if" would be more typical, but still OK for a fix.

What I did later on in the series, was

diff --git a/drivers/gpu/drm/i915/i915_gem_request.c b/drivers/gpu/drm/i915/i915_gem_request.c
index 72b7f7d9461d..c33f537f02b3 100644
--- a/drivers/gpu/drm/i915/i915_gem_request.c
+++ b/drivers/gpu/drm/i915/i915_gem_request.c
@@ -1026,7 +1026,11 @@ __i915_request_wait_for_execute(struct drm_i915_gem_request *request,
                }
 
                timeout = io_schedule_timeout(timeout);
-       } while (timeout);
+               if (!timeout) {
+                       timeout = -ETIME;
+                       break;
+               }
+       } while (1);
        finish_wait(&request->execute.wait, &wait);
 
        if (flags & I915_WAIT_LOCKED)

That seemed like a more consistent pattern to use. Care to consider that as a v2?
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre