[ALSA] usb-audio: show USB error descriptions

Modules: USB generic driver

When usb_submit_urb() fails, show an error description instead of just
the error code.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>

diff --git a/sound/usb/usbaudio.c b/sound/usb/usbaudio.c
index 039f27d..45157d3 100644 (file)
--- a/sound/usb/usbaudio.c
+++ b/sound/usb/usbaudio.c
@@ -773,6 +773,31 @@ static int deactivate_urbs(struct snd_usb_substream *subs, int force, int can_sl
 }
 
 
+static const char *usb_error_string(int err)
+{
+       switch (err) {
+       case -ENODEV:
+               return "no device";
+       case -ENOENT:
+               return "endpoint not enabled";
+       case -EPIPE:
+               return "endpoint stalled";
+       case -ENOSPC:
+               return "not enough bandwidth";
+       case -ESHUTDOWN:
+               return "device disabled";
+       case -EHOSTUNREACH:
+               return "device suspended";
+       case -EINVAL:
+       case -EAGAIN:
+       case -EFBIG:
+       case -EMSGSIZE:
+               return "internal error";
+       default:
+               return "unknown error";
+       }
+}
+
 /*
  * set up and start data/sync urbs
  */
@@ -805,16 +830,22 @@ static int start_urbs(struct snd_usb_substream *subs, struct snd_pcm_runtime *ru
        subs->unlink_mask = 0;
        subs->running = 1;
        for (i = 0; i < subs->nurbs; i++) {
-               if ((err = usb_submit_urb(subs->dataurb[i].urb, GFP_ATOMIC)) < 0) {
-                       snd_printk(KERN_ERR "cannot submit datapipe for urb %d, err = %d\n", i, err);
+               err = usb_submit_urb(subs->dataurb[i].urb, GFP_ATOMIC);
+               if (err < 0) {
+                       snd_printk(KERN_ERR "cannot submit datapipe "
+                                  "for urb %d, error %d: %s\n",
+                                  i, err, usb_error_string(err));
                        goto __error;
                }
                set_bit(i, &subs->active_mask);
        }
        if (subs->syncpipe) {
                for (i = 0; i < SYNC_URBS; i++) {
-                       if ((err = usb_submit_urb(subs->syncurb[i].urb, GFP_ATOMIC)) < 0) {
-                               snd_printk(KERN_ERR "cannot submit syncpipe for urb %d, err = %d\n", i, err);
+                       err = usb_submit_urb(subs->syncurb[i].urb, GFP_ATOMIC);
+                       if (err < 0) {
+                               snd_printk(KERN_ERR "cannot submit syncpipe "
+                                          "for urb %d, error %d: %s\n",
+                                          i, err, usb_error_string(err));
                                goto __error;
                        }
                        set_bit(i + 16, &subs->active_mask);