Commit 83ea5d18 authored Mar 19, 2013 by Daniel Mack Committed by Takashi Iwai Mar 20, 2013

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



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>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

parent 4d7b86c9

sound/usb/mixer.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -2123,7 +2123,7 @@ 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;
		@@ -2135,12 +2135,12 @@ 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;
		}
		}

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