[ALSA] usb-audio: add error message about missing split iso support

Modules: USB generic driver

Add an error message for -ENOSYS for situations when split iso support
is needed but not enabled.

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

diff --git a/sound/usb/usbaudio.c b/sound/usb/usbaudio.c
index 45157d3..6fad2c4 100644 (file)
--- a/sound/usb/usbaudio.c
+++ b/sound/usb/usbaudio.c
@@ -788,6 +788,10 @@ static const char *usb_error_string(int err)
                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: