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[v2,08/13] drm/i915/guc: Wait for doorbell to be inactive before deallocating

Message ID 1490204396-3395-9-git-send-email-oscar.mateo@intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

oscar.mateo@intel.com March 22, 2017, 5:39 p.m. UTC 
Doorbell release flow requires that we wait for GEN8_DRB_VALID bit to go
to zero after updating db_status before we call the GuC to release the
doorbell.

Kudos to Daniele for finding this out.

v2: WARN instead of DRM_ERROR (Joonas)

Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
---
 drivers/gpu/drm/i915/i915_guc_submission.c | 10 ++++++++++
 1 file changed, 10 insertions(+)
diff mbox

Patch

diff --git a/drivers/gpu/drm/i915/i915_guc_submission.c b/drivers/gpu/drm/i915/i915_guc_submission.c
index c02167c..2d4d854 100644
--- a/drivers/gpu/drm/i915/i915_guc_submission.c
+++ b/drivers/gpu/drm/i915/i915_guc_submission.c
@@ -206,12 +206,22 @@  static int __create_doorbell(struct i915_guc_client *client)
 
 static int __destroy_doorbell(struct i915_guc_client *client)
 {
+	struct drm_i915_private *dev_priv = guc_to_i915(client->guc);
 	struct guc_doorbell_info *doorbell;
+	u16 db_id = client->doorbell_id;
+
+	GEM_BUG_ON(db_id >= GUC_DOORBELL_INVALID);
 
 	doorbell = __get_doorbell(client);
 	doorbell->db_status = GUC_DOORBELL_DISABLED;
 	doorbell->cookie = 0;
 
+	/* Doorbell release flow requires that we wait for GEN8_DRB_VALID bit
+	 * to go to zero after updating db_status before we call the GuC to
+	 * release the doorbell */
+	if (wait_for_us(!(I915_READ(GEN8_DRBREGL(db_id)) & GEN8_DRB_VALID), 10))
+		WARN_ONCE(true, "Doorbell never became invalid after disable\n");
+
 	return __guc_deallocate_doorbell(client->guc, client->ctx_index);
 }