[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>

1 files changed, 35 insertions, 4 deletions

diff --git a/sound/usb/usbaudio.c b/sound/usb/usbaudio.c
index 039f27dc1f08..45157d3cf789 100644
--- 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);