From: Clemens Ladisch Date: Thu, 11 Oct 2007 12:15:06 +0000 (+0200) Subject: [ALSA] mpu-401: do not require an ACK byte for the ENTER_UART command X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=69d8d3eb4df40194485b842c00047bb80e51c6a8;p=linux-beck.git [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 --- diff --git a/sound/drivers/mpu401/mpu401_uart.c b/sound/drivers/mpu401/mpu401_uart.c index 85aedc348e2d..b5c5dd1e61bd 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; }