Re: [PATCH] sound: usb: pcm: fix incorrect power state when playing sound after PM_AUTO suspend

From: Takashi Iwai
Date: Wed Jun 03 2020 - 02:54:59 EST


On Wed, 03 Jun 2020 08:28:09 +0200,
Takashi Iwai wrote:
>
> And, the most suspicious case is the last one,
> chip->num_suspended-intf. It means that the device has multiple
> USB interfaces and they went to suspend, while the resume isn't
> performed for the all suspended interfaces in return.

If this is the cause, a patch like below might help.
It gets/puts the all assigned interfaced instead of only the primary
one.


Takashi

---
diff --git a/sound/usb/card.c b/sound/usb/card.c
--- a/sound/usb/card.c
+++ b/sound/usb/card.c
@@ -634,7 +634,6 @@ static int usb_audio_probe(struct usb_interface *intf,
id, &chip);
if (err < 0)
goto __error;
- chip->pm_intf = intf;
break;
} else if (vid[i] != -1 || pid[i] != -1) {
dev_info(&dev->dev,
@@ -651,6 +650,13 @@ static int usb_audio_probe(struct usb_interface *intf,
goto __error;
}
}
+
+ if (chip->num_interfaces >= MAX_CARD_INTERFACES) {
+ dev_info(&dev->dev, "Too many interfaces assigned to the single USB-audio card\n");
+ err = -EINVAL;
+ goto __error;
+ }
+
dev_set_drvdata(&dev->dev, chip);

/*
@@ -703,6 +709,7 @@ static int usb_audio_probe(struct usb_interface *intf,
}

usb_chip[chip->index] = chip;
+ chip->intf[chip->num_interfaces] = intf;
chip->num_interfaces++;
usb_set_intfdata(intf, chip);
atomic_dec(&chip->active);
@@ -818,19 +825,36 @@ void snd_usb_unlock_shutdown(struct snd_usb_audio *chip)

int snd_usb_autoresume(struct snd_usb_audio *chip)
{
+ int i, err;
+
if (atomic_read(&chip->shutdown))
return -EIO;
- if (atomic_inc_return(&chip->active) == 1)
- return usb_autopm_get_interface(chip->pm_intf);
+ if (atomic_inc_return(&chip->active) != 1)
+ return 0;
+
+ for (i = 0; i < chip->num_interfaces; i++) {
+ err = usb_autopm_get_interface(chip->intf[i]);
+ if (err < 0) {
+ /* rollback */
+ while (--i >= 0)
+ usb_autopm_put_interface(chip->intf[i]);
+ return err;
+ }
+ }
return 0;
}

void snd_usb_autosuspend(struct snd_usb_audio *chip)
{
+ int i;
+
if (atomic_read(&chip->shutdown))
return;
- if (atomic_dec_and_test(&chip->active))
- usb_autopm_put_interface(chip->pm_intf);
+ if (!atomic_dec_and_test(&chip->active))
+ return;
+
+ for (i = 0; i < chip->num_interfaces; i++)
+ usb_autopm_put_interface(chip->intf[i]);
}

static int usb_audio_suspend(struct usb_interface *intf, pm_message_t message)
diff --git a/sound/usb/usbaudio.h b/sound/usb/usbaudio.h
--- a/sound/usb/usbaudio.h
+++ b/sound/usb/usbaudio.h
@@ -19,11 +19,13 @@
struct media_device;
struct media_intf_devnode;

+#define MAX_CARD_INTERFACES 16
+
struct snd_usb_audio {
int index;
struct usb_device *dev;
struct snd_card *card;
- struct usb_interface *pm_intf;
+ struct usb_interface *intf[MAX_CARD_INTERFACES];
u32 usb_id;
struct mutex mutex;
unsigned int autosuspended:1;