[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>
diff --git a/sound/drivers/mpu401/mpu401_uart.c b/sound/drivers/mpu401/mpu401_uart.c
index 8687ae3..b49a45c 100644
--- a/sound/drivers/mpu401/mpu401_uart.c
+++ b/sound/drivers/mpu401/mpu401_uart.c
@@ -183,7 +183,8 @@
*/
-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 @@
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 @@
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 @@
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 @@
snd_mpu401_uart_remove_timer(mpu, 1);
clear_bit(MPU401_MODE_BIT_INPUT_TRIGGER, &mpu->mode);
}
+
}
/*