From 69d8d3eb4df40194485b842c00047bb80e51c6a8 Mon Sep 17 00:00:00 2001 From: Clemens Ladisch Date: Thu, 11 Oct 2007 14:15:06 +0200 Subject: [ALSA] mpu-401: do not require an ACK byte for the ENTER_UART command The original MPU-401 does not send an ACK byte after processing the ENTER_UART command, so we better do not try to wait for it. Many clones get this wrong and do send an ACK, but when interpreting it as MIDI, it is just a harmless Active Sensing message, and it is likely to be read and discarded by the interrupt handler before the MIDI input device is triggered. Signed-off-by: Clemens Ladisch Signed-off-by: Jaroslav Kysela --- sound/drivers/mpu401/mpu401_uart.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/sound/drivers/mpu401/mpu401_uart.c b/sound/drivers/mpu401/mpu401_uart.c index 85aedc3..b5c5dd1 100644 --- a/sound/drivers/mpu401/mpu401_uart.c +++ b/sound/drivers/mpu401/mpu401_uart.c @@ -271,7 +271,7 @@ static int snd_mpu401_do_reset(struct snd_mpu401 *mpu) if (snd_mpu401_uart_cmd(mpu, MPU401_RESET, 1)) return -EIO; if (!(mpu->info_flags & MPU401_INFO_UART_ONLY) && - snd_mpu401_uart_cmd(mpu, MPU401_ENTER_UART, 1)) + snd_mpu401_uart_cmd(mpu, MPU401_ENTER_UART, 0)) return -EIO; return 0; } -- cgit v1.1