[PATCH 6.7 074/162] ALSA: firewire-lib: fix to check cycle continuity

Greg Kroah-Hartman
2024-03-04T21:29:05Z

From: Takashi Sakamoto <o-takashi@sakamocchi.jp>

commit 77ce96543b03f437c6b45f286d8110db2b6622a3 upstream.

The local helper function to compare the given pair of cycle count
evaluates them. If the left value is less than the right value, the
function returns negative value.

If the safe cycle is less than the current cycle, it is the case of
cycle lost. However, it is not currently handled properly.

This commit fixes the bug.

Cc: <stable@vger.kernel.org>
Fixes: 705794c53b00 ("ALSA: firewire-lib: check cycle continuity")
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20240218033026.72577-1-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
sound/firewire/amdtp-stream.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/sound/firewire/amdtp-stream.c
+++ b/sound/firewire/amdtp-stream.c
@@ -951,7 +951,7 @@ static int generate_tx_packet_descs(stru
// to the reason.
unsigned int safe_cycle = increment_ohci_cycle_count(next_cycle,
IR_JUMBO_PAYLOAD_MAX_SKIP_CYCLES);
- lost = (compare_ohci_cycle_count(safe_cycle, cycle) > 0);
+ lost = (compare_ohci_cycle_count(safe_cycle, cycle) < 0);
}
if (lost) {
dev_err(&s->unit->device, "Detect discontinuity of cycle: %d %d\n",