drm/i915/pxp/mtl: Update pxp-firmware response timeout

From Alan Previn
8ae272348153ed2fa423f739047a592d9bd55ba2 in mainline linux

Fixes a LG UltraFine 5K display not lighting up on a Comet Lake machine.
Regression reported by Kirill A. Korinsky who tracked the problem down
to a timeout in pxp.

4 files changed, 29 insertions, 9 deletions

diff --git a/sys/dev/pci/drm/i915/gt/uc/intel_gsc_uc_heci_cmd_submit.c b/sys/dev/pci/drm/i915/gt/uc/intel_gsc_uc_heci_cmd_submit.c
index 89ed5ee9cde..2fde5c360cf 100644
--- a/sys/dev/pci/drm/i915/gt/uc/intel_gsc_uc_heci_cmd_submit.c
+++ b/sys/dev/pci/drm/i915/gt/uc/intel_gsc_uc_heci_cmd_submit.c
@@ -81,8 +81,17 @@ out_rq:
 
 	i915_request_add(rq);
 
-	if (!err && i915_request_wait(rq, 0, msecs_to_jiffies(500)) < 0)
-		err = -ETIME;
+	if (!err) {
+		/*
+		 * Start timeout for i915_request_wait only after considering one possible
+		 * pending GSC-HECI submission cycle on the other (non-privileged) path.
+		 */
+		if (wait_for(i915_request_started(rq), GSC_HECI_REPLY_LATENCY_MS))
+			drm_dbg(&gsc_uc_to_gt(gsc)->i915->drm,
+				"Delay in gsc-heci-priv submission to gsccs-hw");
+		if (i915_request_wait(rq, 0, msecs_to_jiffies(GSC_HECI_REPLY_LATENCY_MS)) < 0)
+			err = -ETIME;
+	}
 
 	i915_request_put(rq);
 
@@ -186,6 +195,13 @@ out_rq:
 	i915_request_add(rq);
 
 	if (!err) {
+		/*
+		 * Start timeout for i915_request_wait only after considering one possible
+		 * pending GSC-HECI submission cycle on the other (privileged) path.
+		 */
+		if (wait_for(i915_request_started(rq), GSC_HECI_REPLY_LATENCY_MS))
+			drm_dbg(&gsc_uc_to_gt(gsc)->i915->drm,
+				"Delay in gsc-heci-non-priv submission to gsccs-hw");
 		if (i915_request_wait(rq, I915_WAIT_INTERRUPTIBLE,
 				      msecs_to_jiffies(timeout_ms)) < 0)
 			err = -ETIME;
diff --git a/sys/dev/pci/drm/i915/gt/uc/intel_gsc_uc_heci_cmd_submit.h b/sys/dev/pci/drm/i915/gt/uc/intel_gsc_uc_heci_cmd_submit.h
index 09d3fbdad05..c4308291c00 100644
--- a/sys/dev/pci/drm/i915/gt/uc/intel_gsc_uc_heci_cmd_submit.h
+++ b/sys/dev/pci/drm/i915/gt/uc/intel_gsc_uc_heci_cmd_submit.h
@@ -12,6 +12,12 @@ struct i915_vma;
 struct intel_context;
 struct intel_gsc_uc;
 
+#define GSC_HECI_REPLY_LATENCY_MS 500
+/*
+ * Max FW response time is 500ms, but this should be counted from the time the
+ * command has hit the GSC-CS hardware, not the preceding handoff to GuC CTB.
+ */
+
 struct intel_gsc_mtl_header {
 	u32 validity_marker;
 #define GSC_HECI_VALIDITY_MARKER 0xA578875A
diff --git a/sys/dev/pci/drm/i915/pxp/intel_pxp_gsccs.c b/sys/dev/pci/drm/i915/pxp/intel_pxp_gsccs.c
index 86f58a5bddd..cc81a462492 100644
--- a/sys/dev/pci/drm/i915/pxp/intel_pxp_gsccs.c
+++ b/sys/dev/pci/drm/i915/pxp/intel_pxp_gsccs.c
@@ -111,7 +111,7 @@ gsccs_send_message(struct intel_pxp *pxp,
 
 	ret = intel_gsc_uc_heci_cmd_submit_nonpriv(&gt->uc.gsc,
 						   exec_res->ce, &pkt, exec_res->bb_vaddr,
-						   GSC_REPLY_LATENCY_MS);
+						   GSC_HECI_REPLY_LATENCY_MS);
 	if (ret) {
 		drm_err(&i915->drm, "failed to send gsc PXP msg (%d)\n", ret);
 		goto unlock;
diff --git a/sys/dev/pci/drm/i915/pxp/intel_pxp_gsccs.h b/sys/dev/pci/drm/i915/pxp/intel_pxp_gsccs.h
index 298ad38e6c7..9aae779c4da 100644
--- a/sys/dev/pci/drm/i915/pxp/intel_pxp_gsccs.h
+++ b/sys/dev/pci/drm/i915/pxp/intel_pxp_gsccs.h
@@ -8,16 +8,14 @@
 
 #include <linux/types.h>
 
+#include "gt/uc/intel_gsc_uc_heci_cmd_submit.h"
+
 struct intel_pxp;
 
-#define GSC_REPLY_LATENCY_MS 210
-/*
- * Max FW response time is 200ms, to which we add 10ms to account for overhead
- * such as request preparation, GuC submission to hw and pipeline completion times.
- */
 #define GSC_PENDING_RETRY_MAXCOUNT 40
 #define GSC_PENDING_RETRY_PAUSE_MS 50
-#define GSCFW_MAX_ROUND_TRIP_LATENCY_MS (GSC_PENDING_RETRY_MAXCOUNT * GSC_PENDING_RETRY_PAUSE_MS)
+#define GSCFW_MAX_ROUND_TRIP_LATENCY_MS (GSC_HECI_REPLY_LATENCY_MS + \
+					 (GSC_PENDING_RETRY_MAXCOUNT * GSC_PENDING_RETRY_PAUSE_MS))
 
 #ifdef CONFIG_DRM_I915_PXP
 void intel_pxp_gsccs_fini(struct intel_pxp *pxp);