[ 3.5.y.z extended stable ] Patch "ALSA: snd-usb: mixer: ignore -EINVAL in" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    ALSA: snd-usb: mixer: ignore -EINVAL in

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 353daa7e352da09f23b342b34e6cbbf7feb50113 Mon Sep 17 00:00:00 2001
From: Daniel Mack <zonque at gmail.com>
Date: Tue, 19 Mar 2013 21:09:25 +0100
Subject: [PATCH] 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 at gmail.com>
Reported-and-tested-by: Rodolfo Thomazelli <pe.soberbo at gmail.com>
Signed-off-by: Takashi Iwai <tiwai at suse.de>
Luis Henriques <luis.henriques at canonical.com>
---
 sound/usb/mixer.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index 1b523a1..4d8ddc6 100644
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -2047,7 +2047,7 @@ 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;
@@ -2059,12 +2059,12 @@ 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;
 		}
 	}
--
1.8.1.2