ALSA: usb-audio: Fix missing autopm for MIDI input

The commit [88a8516a: ALSA: usbaudio: implement USB autosuspend] added
the support of autopm for USB MIDI output, but it didn't take the MIDI
input into account.

This patch adds the following for fixing the autopm:
- Manage the URB start at the first MIDI input stream open, instead of
  the time of instance creation
- Move autopm code to the common substream_open()
- Make snd_usbmidi_input_start/_stop() more robust and add the running
  state check

Reviewd-by: Clemens Ladisch <clemens@ladisch.de>
Tested-by: Clemens Ladisch <clemens@ladisch.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 46 insertions, 42 deletions

diff --git a/sound/usb/midi.c b/sound/usb/midi.c
index c0054ee9389b..34b9bb7fe87c 100644
--- a/sound/usb/midi.c
+++ b/sound/usb/midi.c
@@ -126,8 +126,10 @@ struct snd_usb_midi {
                 struct snd_usb_midi_in_endpoint *in;
         } endpoints[MIDI_MAX_ENDPOINTS];
         unsigned long input_triggered;
-        unsigned int opened;
+        bool autopm_reference;
+        unsigned int opened[2];
         unsigned char disconnected;
+        unsigned char input_running;
 
         struct snd_kcontrol *roland_load_ctl;
 };
@@ -149,7 +151,6 @@ struct snd_usb_midi_out_endpoint {
                 struct snd_usb_midi_out_endpoint* ep;
                 struct snd_rawmidi_substream *substream;
                 int active;
-                bool autopm_reference;
                 uint8_t cable;          /* cable number << 4 */
                 uint8_t state;
 #define STATE_UNKNOWN   0
@@ -1034,36 +1035,58 @@ static void update_roland_altsetting(struct snd_usb_midi* umidi)
         snd_usbmidi_input_start(&umidi->list);
 }
 
-static void substream_open(struct snd_rawmidi_substream *substream, int open)
+static int substream_open(struct snd_rawmidi_substream *substream, int dir,
+                          int open)
 {
         struct snd_usb_midi* umidi = substream->rmidi->private_data;
         struct snd_kcontrol *ctl;
+        int err;
 
         down_read(&umidi->disc_rwsem);
         if (umidi->disconnected) {
                 up_read(&umidi->disc_rwsem);
-                return;
+                return open ? -ENODEV : 0;
         }
 
         mutex_lock(&umidi->mutex);
         if (open) {
-                if (umidi->opened++ == 0 && umidi->roland_load_ctl) {
-                        ctl = umidi->roland_load_ctl;
-                        ctl->vd[0].access |= SNDRV_CTL_ELEM_ACCESS_INACTIVE;
-                        snd_ctl_notify(umidi->card,
+                if (!umidi->opened[0] && !umidi->opened[1]) {
+                        err = usb_autopm_get_interface(umidi->iface);
+                        umidi->autopm_reference = err >= 0;
+                        if (err < 0 && err != -EACCES) {
+                                mutex_unlock(&umidi->mutex);
+                                up_read(&umidi->disc_rwsem);
+                                return -EIO;
+                        }
+                        if (umidi->roland_load_ctl) {
+                                ctl = umidi->roland_load_ctl;
+                                ctl->vd[0].access |= SNDRV_CTL_ELEM_ACCESS_INACTIVE;
+                                snd_ctl_notify(umidi->card,
                                        SNDRV_CTL_EVENT_MASK_INFO, &ctl->id);
-                        update_roland_altsetting(umidi);
+                                update_roland_altsetting(umidi);
+                        }
                 }
+                umidi->opened[dir]++;
+                if (umidi->opened[1])
+                        snd_usbmidi_input_start(&umidi->list);
         } else {
-                if (--umidi->opened == 0 && umidi->roland_load_ctl) {
-                        ctl = umidi->roland_load_ctl;
-                        ctl->vd[0].access &= ~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
-                        snd_ctl_notify(umidi->card,
+                umidi->opened[dir]--;
+                if (!umidi->opened[1])
+                        snd_usbmidi_input_stop(&umidi->list);
+                if (!umidi->opened[0] && !umidi->opened[1]) {
+                        if (umidi->roland_load_ctl) {
+                                ctl = umidi->roland_load_ctl;
+                                ctl->vd[0].access &= ~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
+                                snd_ctl_notify(umidi->card,
                                        SNDRV_CTL_EVENT_MASK_INFO, &ctl->id);
+                        }
+                        if (umidi->autopm_reference)
+                                usb_autopm_put_interface(umidi->iface);
                 }
         }
         mutex_unlock(&umidi->mutex);
         up_read(&umidi->disc_rwsem);
+        return 0;
 }
 
 static int snd_usbmidi_output_open(struct snd_rawmidi_substream *substream)
@@ -1071,7 +1094,6 @@ static int snd_usbmidi_output_open(struct snd_rawmidi_substream *substream)
         struct snd_usb_midi* umidi = substream->rmidi->private_data;
         struct usbmidi_out_port* port = NULL;
         int i, j;
-        int err;
 
         for (i = 0; i < MIDI_MAX_ENDPOINTS; ++i)
                 if (umidi->endpoints[i].out)
@@ -1085,33 +1107,14 @@ static int snd_usbmidi_output_open(struct snd_rawmidi_substream *substream)
                 return -ENXIO;
         }
 
-        down_read(&umidi->disc_rwsem);
-        if (umidi->disconnected) {
-                up_read(&umidi->disc_rwsem);
-                return -ENODEV;
-        }
-        err = usb_autopm_get_interface(umidi->iface);
-        port->autopm_reference = err >= 0;
-        up_read(&umidi->disc_rwsem);
-        if (err < 0 && err != -EACCES)
-                return -EIO;
         substream->runtime->private_data = port;
         port->state = STATE_UNKNOWN;
-        substream_open(substream, 1);
-        return 0;
+        return substream_open(substream, 0, 1);
 }
 
 static int snd_usbmidi_output_close(struct snd_rawmidi_substream *substream)
 {
-        struct snd_usb_midi* umidi = substream->rmidi->private_data;
-        struct usbmidi_out_port *port = substream->runtime->private_data;
-
-        substream_open(substream, 0);
-        down_read(&umidi->disc_rwsem);
-        if (!umidi->disconnected && port->autopm_reference)
-                usb_autopm_put_interface(umidi->iface);
-        up_read(&umidi->disc_rwsem);
-        return 0;
+        return substream_open(substream, 0, 0);
 }
 
 static void snd_usbmidi_output_trigger(struct snd_rawmidi_substream *substream, int up)
@@ -1164,14 +1167,12 @@ static void snd_usbmidi_output_drain(struct snd_rawmidi_substream *substream)
 
 static int snd_usbmidi_input_open(struct snd_rawmidi_substream *substream)
 {
-        substream_open(substream, 1);
-        return 0;
+        return substream_open(substream, 1, 1);
 }
 
 static int snd_usbmidi_input_close(struct snd_rawmidi_substream *substream)
 {
-        substream_open(substream, 0);
-        return 0;
+        return substream_open(substream, 1, 0);
 }
 
 static void snd_usbmidi_input_trigger(struct snd_rawmidi_substream *substream, int up)
@@ -2080,12 +2081,15 @@ void snd_usbmidi_input_stop(struct list_head* p)
         unsigned int i, j;
 
         umidi = list_entry(p, struct snd_usb_midi, list);
+        if (!umidi->input_running)
+                return;
         for (i = 0; i < MIDI_MAX_ENDPOINTS; ++i) {
                 struct snd_usb_midi_endpoint* ep = &umidi->endpoints[i];
                 if (ep->in)
                         for (j = 0; j < INPUT_URBS; ++j)
                                 usb_kill_urb(ep->in->urbs[j]);
         }
+        umidi->input_running = 0;
 }
 
 static void snd_usbmidi_input_start_ep(struct snd_usb_midi_in_endpoint* ep)
@@ -2110,8 +2114,11 @@ void snd_usbmidi_input_start(struct list_head* p)
         int i;
 
         umidi = list_entry(p, struct snd_usb_midi, list);
+        if (umidi->input_running || !umidi->opened[1])
+                return;
         for (i = 0; i < MIDI_MAX_ENDPOINTS; ++i)
                 snd_usbmidi_input_start_ep(umidi->endpoints[i].in);
+        umidi->input_running = 1;
 }
 
 /*
@@ -2250,9 +2257,6 @@ int snd_usbmidi_create(struct snd_card *card,
         }
 
         list_add_tail(&umidi->list, midi_list);
-
-        for (i = 0; i < MIDI_MAX_ENDPOINTS; ++i)
-                snd_usbmidi_input_start_ep(umidi->endpoints[i].in);
         return 0;
 }