[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)