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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: Jon Masters <jcm@jonmasters.org>
Cc: Jaroslav Kysela <perex@suse.cz>
Acked-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Jon Masters 2006-04-20 02:43:20 -07:00 committed by Linus Torvalds
parent c79cfbacca
commit 962f831f67
1 changed files with 33 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

42
sound/drivers/mpu401/mpu401_uart.c
View File

@ -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);
}
}
/*