ALSA: snd-usb: mixer: ignore -EINVAL in snd_usb_mixer_controls()

commit 83ea5d18d74f032a760fecde78c0210f66f7f70c upstream.

Creation of individual mixer controls may fail, but that shouldn't cause
the entire mixer creation to fail. Even worse, if the mixer creation
fails, that will error out the entire device probing.

All the functions called by parse_audio_unit() should return -EINVAL if
they find descriptors that are unsupported or believed to be malformed,
so we can safely handle this error code as a non-fatal condition in
snd_usb_mixer_controls().

That fixes a long standing bug which is commonly worked around by
adding quirks which make the driver ignore entire interfaces. Some of
them might now be unnecessary.

Signed-off-by: Daniel Mack <zonque@gmail.com>
Reported-and-tested-by: Rodolfo Thomazelli <pe.soberbo@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index 05159b571668fff677f4a80a2f9262d8b48d77ae..f008fc70d394d581784fe720d51ed3b98d5e0d20 100644 (file)
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -2027,7 +2027,7 @@ static int snd_usb_mixer_controls(struct usb_mixer_interface *mixer)
                        state.oterm.type = le16_to_cpu(desc->wTerminalType);
                        state.oterm.name = desc->iTerminal;
                        err = parse_audio_unit(&state, desc->bSourceID);
-                       if (err < 0)
+                       if (err < 0 && err != -EINVAL)
                                return err;
                } else { /* UAC_VERSION_2 */
                        struct uac2_output_terminal_descriptor *desc = p;
@@ -2039,12 +2039,12 @@ static int snd_usb_mixer_controls(struct usb_mixer_interface *mixer)
                        state.oterm.type = le16_to_cpu(desc->wTerminalType);
                        state.oterm.name = desc->iTerminal;
                        err = parse_audio_unit(&state, desc->bSourceID);
-                       if (err < 0)
+                       if (err < 0 && err != -EINVAL)
                                return err;
 
                        /* for UAC2, use the same approach to also add the clock selectors */
                        err = parse_audio_unit(&state, desc->bCSourceID);
-                       if (err < 0)
+                       if (err < 0 && err != -EINVAL)
                                return err;
                }
        }