As snd_ff.rx_bytes[] is unsigned int, and NSEC_PER_SEC is 1000000000L, the second multiplication in
ff->rx_bytes[port] * 8 * NSEC_PER_SEC / 31250
always overflows on 32-bit platforms, truncating the result. Fix this by precalculating "NSEC_PER_SEC / 31250", which is an integer constant.
Note that this assumes ff->rx_bytes[port] <= 16777.
Fixes: 19174295788de77d ("ALSA: fireface: add transaction support") Signed-off-by: Geert Uytterhoeven geert+renesas@glider.be --- Compile-tested only.
I don't know the maximum transfer length of MIDI, but given it's an old standard, I guess it's rather small. If it is larger than 16777, the constant "8" should be replaced by "8ULL", to force 64-bit arithmetic. --- sound/firewire/fireface/ff-transaction.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sound/firewire/fireface/ff-transaction.c b/sound/firewire/fireface/ff-transaction.c index 7f82762ccc8c80ba..ee7122c461d46f44 100644 --- a/sound/firewire/fireface/ff-transaction.c +++ b/sound/firewire/fireface/ff-transaction.c @@ -88,7 +88,7 @@ static void transmit_midi_msg(struct snd_ff *ff, unsigned int port)
/* Set interval to next transaction. */ ff->next_ktime[port] = ktime_add_ns(ktime_get(), - ff->rx_bytes[port] * 8 * NSEC_PER_SEC / 31250); + ff->rx_bytes[port] * 8 * (NSEC_PER_SEC / 31250));
if (quad_count == 1) tcode = TCODE_WRITE_QUADLET_REQUEST;