ALSA: jack: Unregister input device at disconnection

The recent change in sysfs triggered a kernel WARNING at unloading a
sound driver like

  WARNING: CPU: 3 PID: 2247 at fs/sysfs/group.c:214 sysfs_remove_group+0xe8/0xf0()
  sysfs group ffffffff81ab7b20 not found for kobject 'event14'

for each jack instance.  It's because the unregistration of jack input
device is done in dev_free callback, which is called after
snd_card_disconnect().  Since device_unregister(card->card_dev) is
called in snd_card_disconnect(), the whole sysfs entries belonging to
card->card_dev have been already removed recursively.  Thus this
results in a warning as input_unregister_device() yet tries to
unregister the already removed sysfs entry.

For fixing this mess, we need to unregister the jack input device at
dev_disconnect callback so that it's called before unregistering the
card->card_dev.

Reviwed-by: Mark Brown <broonie@linaro.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/core/jack.c b/sound/core/jack.c
index b35fe73..8658578 100644 (file)
--- a/sound/core/jack.c
+++ b/sound/core/jack.c
@@ -34,12 +34,12 @@ static int jack_switch_types[SND_JACK_SWITCH_TYPES] = {
        SW_LINEIN_INSERT,
 };
 
-static int snd_jack_dev_free(struct snd_device *device)
+static int snd_jack_dev_disconnect(struct snd_device *device)
 {
        struct snd_jack *jack = device->device_data;
 
-       if (jack->private_free)
-               jack->private_free(jack);
+       if (!jack->input_dev)
+               return 0;
 
        /* If the input device is registered with the input subsystem
         * then we need to use a different deallocator. */
@@ -47,6 +47,18 @@ static int snd_jack_dev_free(struct snd_device *device)
                input_unregister_device(jack->input_dev);
        else
                input_free_device(jack->input_dev);
+       jack->input_dev = NULL;
+       return 0;
+}
+
+static int snd_jack_dev_free(struct snd_device *device)
+{
+       struct snd_jack *jack = device->device_data;
+
+       if (jack->private_free)
+               jack->private_free(jack);
+
+       snd_jack_dev_disconnect(device);
 
        kfree(jack->id);
        kfree(jack);
@@ -110,6 +122,7 @@ int snd_jack_new(struct snd_card *card, const char *id, int type,
        static struct snd_device_ops ops = {
                .dev_free = snd_jack_dev_free,
                .dev_register = snd_jack_dev_register,
+               .dev_disconnect = snd_jack_dev_disconnect,
        };
 
        jack = kzalloc(sizeof(struct snd_jack), GFP_KERNEL);