1 files changed, 48 insertions, 27 deletions

diff --git a/kernel/gsp_display_engine.c b/kernel/gsp_display_engine.c
index f96fc6a..c7c9dca 100644
--- a/kernel/gsp_display_engine.c
+++ b/kernel/gsp_display_engine.c
@@ -101,6 +101,11 @@
 #define GSP_DISP_NOTIFIER_CTRL_NOTIFY	BIT(12)
 /* The CONTROL offset field is in 16-byte units; expose it in bytes. */
 #define GSP_DISP_NOTIFIER_CTRL_OFFSET(c) ((((c) >> 4) & 0xff) * 16)
+/* Coalesce a refused completion wake-up, then re-post it.  Must be at least
+ * the RM event hint dedup window (HZ / 4 = 250 ms) so the retry is not
+ * coalesced into the same post that starved it; at most four attempts/s per
+ * waiting channel. */
+#define GSP_DISP_EVENT_RETRY_MS		250
 
 /* Display instance memory (v03_00 layout). */
 #define GSP_DISP_INST_HASH_OFF		0x0000
@@ -136,6 +141,7 @@ struct gsp_disp_chan {
 	u32 notifier_writes;
 	u32 notifier_posts;
 	bool event_pending;	/* completion event send failed; retry in pump */
+	unsigned long event_retry_at;	/* next forced re-post attempt */
 	u32 event_drop_logs;
 	u32 update_logs;
 
@@ -1115,6 +1121,8 @@ static void gsp_disp_method(struct nv_vgpu_device *vgpu,
 				 * pump instead of giving up.
 				 */
 				ch->event_pending = true;
+				ch->event_retry_at = jiffies +
+					msecs_to_jiffies(GSP_DISP_EVENT_RETRY_MS);
 				if (ch->event_drop_logs < 8) {
 					ch->event_drop_logs++;
 					pr_info("h=0x%x UPDATE completion event deferred rc=%d (hObj=0x%x)\n",
@@ -1353,39 +1361,51 @@ void gsp_disp_engine_pump(struct nv_vgpu_device *vgpu)
 				s->hclass, s->instance, put, s->consumed,
 				s->ctl_off);
 		}
-		if (put == s->consumed)
-			continue;
-
-		gsp_disp_run(vgpu, s, put);
+		if (put != s->consumed) {
+			gsp_disp_run(vgpu, s, put);
 
-		/*
-		 * Publish our read pointer; the driver's nvEvoMakeRoom and
-		 * EvoCoreReadGet rely on it to reuse the ring.
-		 */
-		gsp_disp_bar0_write(vgpu, s->ctl_off + GSP_DISP_REG_GET,
-				    s->consumed);
-		get = gsp_disp_bar0_read(vgpu,
-					 s->ctl_off + GSP_DISP_REG_GET);
-
-		if (disp.log_budget < 4096) {
-			u64 age = (u64)(now - disp.boot_jiffies) *
-				  (NSEC_PER_SEC / HZ);
-
-			disp.log_budget++;
-			pr_info("pump h=0x%x inst=%u put=0x%x get=0x%x consumed=0x%x at %llu ms\n",
-				s->hclass, s->instance, put, get, s->consumed,
-				div_u64(age, 1000000));
+			/*
+			 * Publish our read pointer; the driver's nvEvoMakeRoom
+			 * and EvoCoreReadGet rely on it to reuse the ring.
+			 */
+			gsp_disp_bar0_write(vgpu, s->ctl_off + GSP_DISP_REG_GET,
+					    s->consumed);
+			get = gsp_disp_bar0_read(vgpu,
+						 s->ctl_off + GSP_DISP_REG_GET);
+
+			if (disp.log_budget < 4096) {
+				u64 age = (u64)(now - disp.boot_jiffies) *
+					  (NSEC_PER_SEC / HZ);
+
+				disp.log_budget++;
+				pr_info("pump h=0x%x inst=%u put=0x%x get=0x%x consumed=0x%x at %llu ms\n",
+					s->hclass, s->instance, put, get,
+					s->consumed, div_u64(age, 1000000));
+			}
 		}
 
 		/*
-		 * Retry a completion event whose send was refused (burst
-		 * cap / transient queue state).  Runs outside disp.lock:
-		 * the post takes the RM status-queue lock.
+		 * Retry a completion event whose send was refused (burst cap /
+		 * transient queue state, or the hint dedup coalescing it into a
+		 * post the waiter never saw).  Runs outside disp.lock (the post
+		 * takes the RM status-queue lock) and on idle passes too: the
+		 * fatal case is an UPDATE that is the channel's last push, so a
+		 * retry gated on new work never runs (r1649).  The forced post
+		 * ignores the per-event hint dedup; the retry window bounds it
+		 * to one attempt per 250 ms per waiting channel while the burst
+		 * cap still guards the status ring.
 		 */
 		if (s->event_pending && s->h_object && gsp_disp_events &&
-		    !gsp_rm_post_channel_event(vgpu, s->h_object)) {
-			s->event_pending = false;
-			s->notifier_posts++;
+		    time_after_eq(jiffies, s->event_retry_at)) {
+			if (!gsp_rm_post_channel_event_force(vgpu, s->h_object)) {
+				s->event_pending = false;
+				s->notifier_posts++;
+				pr_info("h=0x%x UPDATE completion event re-posted after deferral (posts=%u)\n",
+					s->hclass, s->notifier_posts);
+			} else {
+				s->event_retry_at = jiffies +
+					msecs_to_jiffies(GSP_DISP_EVENT_RETRY_MS);
+			}
 		}
 
 		/* Write the bookkeeping back if the slot still names this
@@ -1412,6 +1432,7 @@ void gsp_disp_engine_pump(struct nv_vgpu_device *vgpu)
 				c->notifier_writes = s->notifier_writes;
 				c->notifier_posts = s->notifier_posts;
 				c->event_pending = s->event_pending;
+				c->event_retry_at = s->event_retry_at;
 				c->event_drop_logs = s->event_drop_logs;
 				c->update_logs = s->update_logs;
 				c->logged_update = s->logged_update;