[ALSA] Fix no mpu401 interface can cause hard freeze

This patch fixes the remaining instances in our tree where a non-
existent mpu401 interface can cause a hard freeze when i/o is issued.
This commit closes Malone #34831.
Bug: https://launchpad.net/distros/ubuntu/+source/linux-source-2.6.15/+bug/34831
patch location:
http://www.kernel.org/git/?p=linux/kernel/git/bcollins/ubuntu-dapper.git;a=commitdiff;h=b422309cdd980cfefe99379796c04e961d3c1544
From: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>

1 files changed, 25 insertions, 10 deletions

diff --git a/sound/pci/emu10k1/emumpu401.c b/sound/pci/emu10k1/emumpu401.c
index d96eb455103f..950c6bcd6b7d 100644
--- a/sound/pci/emu10k1/emumpu401.c
+++ b/sound/pci/emu10k1/emumpu401.c
@@ -116,7 +116,7 @@ static void snd_emu10k1_midi_interrupt2(struct snd_emu10k1 *emu, unsigned int st
 	do_emu10k1_midi_interrupt(emu, &emu->midi2, status);
 }
 
-static void snd_emu10k1_midi_cmd(struct snd_emu10k1 * emu, struct snd_emu10k1_midi *midi, unsigned char cmd, int ack)
+static int snd_emu10k1_midi_cmd(struct snd_emu10k1 * emu, struct snd_emu10k1_midi *midi, unsigned char cmd, int ack)
 {
 	unsigned long flags;
 	int timeout, ok;
@@ -141,11 +141,14 @@ static void snd_emu10k1_midi_cmd(struct snd_emu10k1 * emu, struct snd_emu10k1_mi
 		ok = 1;
 	}
 	spin_unlock_irqrestore(&midi->input_lock, flags);
-	if (!ok)
+	if (!ok) {
 		snd_printk(KERN_ERR "midi_cmd: 0x%x failed at 0x%lx (status = 0x%x, data = 0x%x)!!!\n",
 			   cmd, emu->port,
 			   mpu401_read_stat(emu, midi),
 			   mpu401_read_data(emu, midi));
+		return 1;
+	}
+	return 0;
 }
 
 static int snd_emu10k1_midi_input_open(struct snd_rawmidi_substream *substream)
@@ -161,12 +164,17 @@ static int snd_emu10k1_midi_input_open(struct snd_rawmidi_substream *substream)
 	midi->substream_input = substream;
 	if (!(midi->midi_mode & EMU10K1_MIDI_MODE_OUTPUT)) {
 		spin_unlock_irqrestore(&midi->open_lock, flags);
-		snd_emu10k1_midi_cmd(emu, midi, MPU401_RESET, 1);
-		snd_emu10k1_midi_cmd(emu, midi, MPU401_ENTER_UART, 1);
+		if (snd_emu10k1_midi_cmd(emu, midi, MPU401_RESET, 1))
+			goto error_out;
+		if (snd_emu10k1_midi_cmd(emu, midi, MPU401_ENTER_UART, 1))
+			goto error_out;
 	} else {
 		spin_unlock_irqrestore(&midi->open_lock, flags);
 	}
 	return 0;
+
+error_out:
+	return -EIO;
 }
 
 static int snd_emu10k1_midi_output_open(struct snd_rawmidi_substream *substream)
@@ -182,12 +190,17 @@ static int snd_emu10k1_midi_output_open(struct snd_rawmidi_substream *substream)
 	midi->substream_output = substream;
 	if (!(midi->midi_mode & EMU10K1_MIDI_MODE_INPUT)) {
 		spin_unlock_irqrestore(&midi->open_lock, flags);
-		snd_emu10k1_midi_cmd(emu, midi, MPU401_RESET, 1);
-		snd_emu10k1_midi_cmd(emu, midi, MPU401_ENTER_UART, 1);
+		if (snd_emu10k1_midi_cmd(emu, midi, MPU401_RESET, 1))
+			goto error_out;
+		if (snd_emu10k1_midi_cmd(emu, midi, MPU401_ENTER_UART, 1))
+			goto error_out;
 	} else {
 		spin_unlock_irqrestore(&midi->open_lock, flags);
 	}
 	return 0;
+
+error_out:
+	return -EIO;
 }
 
 static int snd_emu10k1_midi_input_close(struct snd_rawmidi_substream *substream)
@@ -195,6 +208,7 @@ static int snd_emu10k1_midi_input_close(struct snd_rawmidi_substream *substream)
 	struct snd_emu10k1 *emu;
 	struct snd_emu10k1_midi *midi = (struct snd_emu10k1_midi *)substream->rmidi->private_data;
 	unsigned long flags;
+	int err = 0;
 
 	emu = midi->emu;
 	snd_assert(emu, return -ENXIO);
@@ -204,11 +218,11 @@ static int snd_emu10k1_midi_input_close(struct snd_rawmidi_substream *substream)
 	midi->substream_input = NULL;
 	if (!(midi->midi_mode & EMU10K1_MIDI_MODE_OUTPUT)) {
 		spin_unlock_irqrestore(&midi->open_lock, flags);
-		snd_emu10k1_midi_cmd(emu, midi, MPU401_RESET, 0);
+		err = snd_emu10k1_midi_cmd(emu, midi, MPU401_RESET, 0);
 	} else {
 		spin_unlock_irqrestore(&midi->open_lock, flags);
 	}
-	return 0;
+	return err;
 }
 
 static int snd_emu10k1_midi_output_close(struct snd_rawmidi_substream *substream)
@@ -216,6 +230,7 @@ static int snd_emu10k1_midi_output_close(struct snd_rawmidi_substream *substream
 	struct snd_emu10k1 *emu;
 	struct snd_emu10k1_midi *midi = (struct snd_emu10k1_midi *)substream->rmidi->private_data;
 	unsigned long flags;
+	int err = 0;
 
 	emu = midi->emu;
 	snd_assert(emu, return -ENXIO);
@@ -225,11 +240,11 @@ static int snd_emu10k1_midi_output_close(struct snd_rawmidi_substream *substream
 	midi->substream_output = NULL;
 	if (!(midi->midi_mode & EMU10K1_MIDI_MODE_INPUT)) {
 		spin_unlock_irqrestore(&midi->open_lock, flags);
-		snd_emu10k1_midi_cmd(emu, midi, MPU401_RESET, 0);
+		err = snd_emu10k1_midi_cmd(emu, midi, MPU401_RESET, 0);
 	} else {
 		spin_unlock_irqrestore(&midi->open_lock, flags);
 	}
-	return 0;
+	return err;
 }
 
 static void snd_emu10k1_midi_input_trigger(struct snd_rawmidi_substream *substream, int up)