drm/i915/gt: Treat a busy timeline as 'active' while waiting

If we cannot claim the timeline->mutex while preparing for a wait on it,
we have to skip the timeline. In doing so, treat it as active so that
under a intel_gt_wait_for_idle() loop, we repeat the wait after
scheduling away.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191006165002.30312-4-chris@chris-wilson.co.uk

diff --git a/drivers/gpu/drm/i915/gt/intel_gt_requests.c b/drivers/gpu/drm/i915/gt/intel_gt_requests.c
index d69e78478eeac9b31115ece39a6f8fea9e7420fa..ca606b79fd5e821e81ee67b03eee1e9178648a0a 100644 (file)
--- a/drivers/gpu/drm/i915/gt/intel_gt_requests.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt_requests.c
@@ -34,8 +34,10 @@ long intel_gt_retire_requests_timeout(struct intel_gt *gt, long timeout)
 
        spin_lock_irqsave(&timelines->lock, flags);
        list_for_each_entry_safe(tl, tn, &timelines->active_list, link) {
-               if (!mutex_trylock(&tl->mutex))
+               if (!mutex_trylock(&tl->mutex)) {
+                       active_count++; /* report busy to caller, try again? */
                        continue;
+               }
 
                intel_timeline_get(tl);
                GEM_BUG_ON(!tl->active_count);