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

commit f5f165418cabf2218eb466c0e94693b8b1aee88b upstream.

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>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/sound/usb/midi.c b/sound/usb/midi.c
index c0054ee9389bcdef91cd97a27dfe95073dd768a9..34b9bb7fe87c8eabed83df8b7b77f510bedbc2b1 100644 (file)
--- 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;
 }