Merging upstream version 5.10.216.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 30 insertions, 2 deletions

diff --git a/drivers/firewire/core-card.c b/drivers/firewire/core-card.c
index f3b3953ca..d446a7262 100644
--- a/drivers/firewire/core-card.c
+++ b/drivers/firewire/core-card.c
@@ -429,7 +429,23 @@ static void bm_work(struct work_struct *work)
 	 */
 	card->bm_generation = generation;
 
-	if (root_device == NULL) {
+	if (card->gap_count == 0) {
+		/*
+		 * If self IDs have inconsistent gap counts, do a
+		 * bus reset ASAP. The config rom read might never
+		 * complete, so don't wait for it. However, still
+		 * send a PHY configuration packet prior to the
+		 * bus reset. The PHY configuration packet might
+		 * fail, but 1394-2008 8.4.5.2 explicitly permits
+		 * it in this case, so it should be safe to try.
+		 */
+		new_root_id = local_id;
+		/*
+		 * We must always send a bus reset if the gap count
+		 * is inconsistent, so bypass the 5-reset limit.
+		 */
+		card->bm_retries = 0;
+	} else if (root_device == NULL) {
 		/*
 		 * Either link_on is false, or we failed to read the
 		 * config rom.  In either case, pick another root.
@@ -484,7 +500,19 @@ static void bm_work(struct work_struct *work)
 		fw_notice(card, "phy config: new root=%x, gap_count=%d\n",
 			  new_root_id, gap_count);
 		fw_send_phy_config(card, new_root_id, generation, gap_count);
-		reset_bus(card, true);
+		/*
+		 * Where possible, use a short bus reset to minimize
+		 * disruption to isochronous transfers. But in the event
+		 * of a gap count inconsistency, use a long bus reset.
+		 *
+		 * As noted in 1394a 8.4.6.2, nodes on a mixed 1394/1394a bus
+		 * may set different gap counts after a bus reset. On a mixed
+		 * 1394/1394a bus, a short bus reset can get doubled. Some
+		 * nodes may treat the double reset as one bus reset and others
+		 * may treat it as two, causing a gap count inconsistency
+		 * again. Using a long bus reset prevents this.
+		 */
+		reset_bus(card, card->gap_count != 0);
 		/* Will allocate broadcast channel after the reset. */
 		goto out;
 	}