[PATCH] [UBUNTU:sound/usb] Make error messages more informative

[crimsun at fungus.sh.nu]

Subject: [PATCH] [UBUNTU:sound/usb] Make error messages more informative

UpstreamStatus: Added in upstream usb/usbaudio.c r1.17[34]

Clemens Ladisch <clemens at ladisch.de> committed the above patch(es) so
that error messages in usb/usbaudio.c are more human-friendly than
simply returning error codes. This change is useful for people who,
for instance, attempt to play audio through a usb device connected to
a hub.

Signed-off-by: Daniel T Chen <crimsun at ubuntu.com>

---

 sound/usb/usbaudio.c |   43 +++++++++++++++++++++++++++++++++++++++----
 1 files changed, 39 insertions(+), 4 deletions(-)

cffcd85ecb3a6d75a446f1dec108b663c8fda9ed
diff --git a/sound/usb/usbaudio.c b/sound/usb/usbaudio.c
index cb73297..e0e6a42 100644
--- a/sound/usb/usbaudio.c
+++ b/sound/usb/usbaudio.c
@@ -781,6 +781,35 @@ static int deactivate_urbs(snd_usb_subst
 }
 
 
+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";
+#ifndef CONFIG_USB_EHCI_SPLIT_ISO
+	case -ENOSYS:
+		return "enable CONFIG_USB_EHCI_SPLIT_ISO to play through a hub";
+#endif
+	case -EINVAL:
+	case -EAGAIN:
+	case -EFBIG:
+	case -EMSGSIZE:
+		return "internal error";
+	default:
+		return "unknown error";
+	}
+}
+
 /*
  * set up and start data/sync urbs
  */
@@ -813,16 +842,22 @@ static int start_urbs(snd_usb_substream_
 	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);
-- 
1.1.3


-- 
Daniel T. Chen            crimsun at ubuntu.com
GPG key:   www.sh.nu/~crimsun/pubkey.gpg.asc
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