drm/i915: Added scheduler flush calls to ring throttle and idle functions

When requesting that all GPU work is completed, it is now necessary to
get the scheduler involved in order to flush out work that queued and
not yet submitted.

v2: Updated to add support for flushing the scheduler queue by time
stamp rather than just doing a blanket flush.

v3: Moved submit_max_priority() to this patch from an earlier patch
is it is no longer required in the other.

v4: Corrected the format of a comment to keep the style checker happy.
Downgraded a BUG_ON to a WARN_ON as the latter is preferred.

v5: Shuffled functions around to remove forward prototypes, removed
similarly offensive white space and added documentation. Re-worked the
mutex locking around the submit function. [Joonas Lahtinen]

Used lighter weight spinlocks.

For: VIZ-1587
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

1 files changed, 23 insertions, 1 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 33c4e40f6844..682ca62f147d 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -3812,6 +3812,10 @@ int i915_gpu_idle(struct drm_device *dev)
 
 	/* Flush everything onto the inactive list. */
 	for_each_engine(engine, dev_priv, i) {
+		ret = i915_scheduler_flush(engine, true);
+		if (ret < 0)
+			return ret;
+
 		if (!i915.enable_execlists) {
 			struct drm_i915_gem_request *req;
 
@@ -4545,7 +4549,8 @@ i915_gem_ring_throttle(struct drm_device *dev, struct drm_file *file)
 	unsigned long recent_enough = jiffies - DRM_I915_THROTTLE_JIFFIES;
 	struct drm_i915_gem_request *request, *target = NULL;
 	unsigned reset_counter;
-	int ret;
+	int i, ret;
+	struct intel_engine_cs *engine;
 
 	ret = i915_gem_wait_for_error(&dev_priv->gpu_error);
 	if (ret)
@@ -4555,6 +4560,23 @@ i915_gem_ring_throttle(struct drm_device *dev, struct drm_file *file)
 	if (ret)
 		return ret;
 
+	for_each_engine(engine, dev_priv, i) {
+		/*
+		 * Flush out scheduler entries that are getting 'stale'. Note
+		 * that the following recent_enough test will only check
+		 * against the time at which the request was submitted to the
+		 * hardware (i.e. when it left the scheduler) not the time it
+		 * was submitted to the driver.
+		 *
+		 * Also, there is not much point worring about busy return
+		 * codes from the scheduler flush call. Even if more work
+		 * cannot be submitted right now for whatever reason, we
+		 * still want to throttle against stale work that has already
+		 * been submitted.
+		 */
+		i915_scheduler_flush_stamp(engine, recent_enough, false);
+	}
+
 	spin_lock(&file_priv->mm.lock);
 	list_for_each_entry(request, &file_priv->mm.request_list, client_list) {
 		if (time_after_eq(request->emitted_jiffies, recent_enough))