[Intel-gfx] [PATCH 1/2] drm/i915: Split gt cache flushing and gt idling functions

[Andi Shyti <andi.shyti@linux.intel.com>]

In preparation for multi-gt cache flushing debugfs interface,
split the cache dropping function and gt idling.

Based on a patch by Tvrtko.

Signed-off-by: Andi Shyti <andi.shyti@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
---
 drivers/gpu/drm/i915/i915_debugfs.c | 32 +++++++++++++++++++++--------
 1 file changed, 24 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 7a90a2e32c9f1..3dfe8a8b7cdfe 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -703,11 +703,25 @@ i915_drop_caches_get(void *data, u64 *val)
 	return 0;
 }
 
+static int gt_idle(struct intel_gt *gt, u64 val)
+{
+	if (val & (DROP_RETIRE | DROP_IDLE))
+		intel_gt_retire_requests(gt);
+
+	if (val & DROP_IDLE) {
+		int ret;
+
+		ret = intel_gt_pm_wait_for_idle(gt);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
 static int
 gt_drop_caches(struct intel_gt *gt, u64 val)
 {
-	int ret;
-
 	if (val & DROP_RESET_ACTIVE &&
 	    wait_for(intel_engines_are_idle(gt), 200))
 		intel_gt_set_wedged(gt);
@@ -716,13 +730,9 @@ gt_drop_caches(struct intel_gt *gt, u64 val)
 		intel_gt_retire_requests(gt);
 
 	if (val & (DROP_IDLE | DROP_ACTIVE)) {
-		ret = intel_gt_wait_for_idle(gt, MAX_SCHEDULE_TIMEOUT);
-		if (ret)
-			return ret;
-	}
+		int ret;
 
-	if (val & DROP_IDLE) {
-		ret = intel_gt_pm_wait_for_idle(gt);
+		ret = intel_gt_wait_for_idle(gt, MAX_SCHEDULE_TIMEOUT);
 		if (ret)
 			return ret;
 	}
@@ -746,10 +756,16 @@ i915_drop_caches_set(void *data, u64 val)
 	drm_dbg(&i915->drm, "Dropping caches: 0x%08llx [0x%08llx]\n",
 		val, val & DROP_ALL);
 
+	/* Flush all the active requests across both GT ... */
 	ret = gt_drop_caches(to_gt(i915), val);
 	if (ret)
 		return ret;
 
+	/* ... then wait for idle as there may be cross-gt wakerefs. */
+	ret = gt_idle(to_gt(i915), val);
+	if (ret)
+		return ret;
+
 	fs_reclaim_acquire(GFP_KERNEL);
 	flags = memalloc_noreclaim_save();
 	if (val & DROP_BOUND)
-- 
2.40.1