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Commit ea6b5828 authored by Clemens Ladisch's avatar Clemens Ladisch Committed by Takashi Iwai
Browse files

[ALSA] mpu401: reduce tx loop timeout 



Reduce the number of times to check for a non-empty Tx FIFO from 100 to
2 because there is no MPU-401 implementation that needs more than one or
two reads to determine the actual FIFO status.

Signed-off-by: default avatarClemens Ladisch <clemens@ladisch.de>
parent 47ba97f8

sound/drivers/mpu401/mpu401_uart.c

+7 −6
Original line number Diff line number Diff line
@@ -425,16 +425,17 @@ static void snd_mpu401_uart_input_read(struct snd_mpu401 * mpu) 
static void snd_mpu401_uart_output_write(struct snd_mpu401 * mpu)

{

	unsigned char byte;

	int max = 256, timeout;

	int max = 256;



	do {

		if (snd_rawmidi_transmit_peek(mpu->substream_output,

					      &byte, 1) == 1) {

			for (timeout = 100; timeout > 0; timeout--) {

				if (snd_mpu401_output_ready(mpu))

					break;

			}

			if (timeout == 0)

			/*

			 * Try twice because there is hardware that insists on

			 * setting the output busy bit after each write.

			 */

			if (!snd_mpu401_output_ready(mpu) &&

			    !snd_mpu401_output_ready(mpu))

				break;	/* Tx FIFO full - try again later */

			mpu->write(mpu, byte, MPU401D(mpu));

			snd_rawmidi_transmit_ack(mpu->substream_output, 1);