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Commit 962f831f authored by Jon Masters's avatar Jon Masters Committed by Linus Torvalds
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[PATCH] sound: fix hang in mpu401_uart.c 



This fixes a hang in mpu401_uart.c that can occur when the mpu401 interface
is non-existent or otherwise doesn't respond to commands but we issue IO
anyway.  snd_mpu401_uart_cmd now returns an error code that is passed up
the stack so that an open() will fail immediately in such cases.

Eventually discovered after wine/cxoffice would constantly cause hard
lockups on my desktop immediately after loading (emulating Windows too
well).  Turned out that I'd recently moved my sound cards around and using
/dev/sequencer now talks to a sound card with a broken MPU.

This second version changes -EFAULT to -EIO and frees open resources on
error too.  Test booted and seems to work ok.

Signed-off-by: default avatarJon Masters <jcm@jonmasters.org>
Cc: Jaroslav Kysela <perex@suse.cz>
Acked-by: default avatarTakashi Iwai <tiwai@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent c79cfbac

sound/drivers/mpu401/mpu401_uart.c

+33 −9
Original line number Diff line number Diff line
@@ -183,7 +183,8 @@ static void snd_mpu401_uart_remove_timer (struct snd_mpu401 *mpu, int input) 


 */



static void snd_mpu401_uart_cmd(struct snd_mpu401 * mpu, unsigned char cmd, int ack)

static int snd_mpu401_uart_cmd(struct snd_mpu401 * mpu, unsigned char cmd,

		int ack)

{

	unsigned long flags;

	int timeout, ok;
@@ -218,9 +219,11 @@ static void snd_mpu401_uart_cmd(struct snd_mpu401 * mpu, unsigned char cmd, int 
		ok = 1;

	}

	spin_unlock_irqrestore(&mpu->input_lock, flags);

	if (! ok)

	if (!ok) {

		snd_printk("cmd: 0x%x failed at 0x%lx (status = 0x%x, data = 0x%x)\n", cmd, mpu->port, mpu->read(mpu, MPU401C(mpu)), mpu->read(mpu, MPU401D(mpu)));

	// snd_printk("cmd: 0x%x at 0x%lx (status = 0x%x, data = 0x%x)\n", cmd, mpu->port, mpu->read(mpu, MPU401C(mpu)), mpu->read(mpu, MPU401D(mpu)));

		return 1;

	}

	return 0;

}



/*
@@ -235,12 +238,19 @@ static int snd_mpu401_uart_input_open(struct snd_rawmidi_substream *substream) 
	if (mpu->open_input && (err = mpu->open_input(mpu)) < 0)

		return err;

	if (! test_bit(MPU401_MODE_BIT_OUTPUT, &mpu->mode)) {

		snd_mpu401_uart_cmd(mpu, MPU401_RESET, 1);

		snd_mpu401_uart_cmd(mpu, MPU401_ENTER_UART, 1);

		if (snd_mpu401_uart_cmd(mpu, MPU401_RESET, 1))

			goto error_out;

		if (snd_mpu401_uart_cmd(mpu, MPU401_ENTER_UART, 1))

			goto error_out;

	}

	mpu->substream_input = substream;

	set_bit(MPU401_MODE_BIT_INPUT, &mpu->mode);

	return 0;



error_out:

	if (mpu->open_input && mpu->close_input)

		mpu->close_input(mpu);

	return -EIO;

}



static int snd_mpu401_uart_output_open(struct snd_rawmidi_substream *substream)
@@ -252,39 +262,52 @@ static int snd_mpu401_uart_output_open(struct snd_rawmidi_substream *substream) 
	if (mpu->open_output && (err = mpu->open_output(mpu)) < 0)

		return err;

	if (! test_bit(MPU401_MODE_BIT_INPUT, &mpu->mode)) {

		snd_mpu401_uart_cmd(mpu, MPU401_RESET, 1);

		snd_mpu401_uart_cmd(mpu, MPU401_ENTER_UART, 1);

		if (snd_mpu401_uart_cmd(mpu, MPU401_RESET, 1))

			goto error_out;

		if (snd_mpu401_uart_cmd(mpu, MPU401_ENTER_UART, 1))

			goto error_out;

	}

	mpu->substream_output = substream;

	set_bit(MPU401_MODE_BIT_OUTPUT, &mpu->mode);

	return 0;



error_out:

	if (mpu->open_output && mpu->close_output)

		mpu->close_output(mpu);

	return -EIO;

}



static int snd_mpu401_uart_input_close(struct snd_rawmidi_substream *substream)

{

	struct snd_mpu401 *mpu;

	int err = 0;



	mpu = substream->rmidi->private_data;

	clear_bit(MPU401_MODE_BIT_INPUT, &mpu->mode);

	mpu->substream_input = NULL;

	if (! test_bit(MPU401_MODE_BIT_OUTPUT, &mpu->mode))

		snd_mpu401_uart_cmd(mpu, MPU401_RESET, 0);

		err = snd_mpu401_uart_cmd(mpu, MPU401_RESET, 0);

	if (mpu->close_input)

		mpu->close_input(mpu);

	if (err)

		return -EIO;

	return 0;

}



static int snd_mpu401_uart_output_close(struct snd_rawmidi_substream *substream)

{

	struct snd_mpu401 *mpu;

	int err = 0;



	mpu = substream->rmidi->private_data;

	clear_bit(MPU401_MODE_BIT_OUTPUT, &mpu->mode);

	mpu->substream_output = NULL;

	if (! test_bit(MPU401_MODE_BIT_INPUT, &mpu->mode))

		snd_mpu401_uart_cmd(mpu, MPU401_RESET, 0);

		err = snd_mpu401_uart_cmd(mpu, MPU401_RESET, 0);

	if (mpu->close_output)

		mpu->close_output(mpu);

	if (err)

		return -EIO;

	return 0;

}
@@ -316,6 +339,7 @@ static void snd_mpu401_uart_input_trigger(struct snd_rawmidi_substream *substrea 
			snd_mpu401_uart_remove_timer(mpu, 1);

		clear_bit(MPU401_MODE_BIT_INPUT_TRIGGER, &mpu->mode);

	}



}



/*