[v2.6.34-stable 44/77] ALSA: hda/realtek - Fix Oops in alc_mux_select()

Paul Gortmaker
2013-01-08T23:38:00Z

From: Takashi Iwai <tiwai@suse.de>

-------------------
This is a commit scheduled for the next v2.6.34 longterm release.
http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git
If you see a problem with using this for longterm, please comment.
-------------------

commit cce4aa378a049f4275416ee6302dd24f37b289df upstream.

When no imux is available (e.g. a single capture source),
alc_auto_init_input_src() may trigger an Oops due to the access to -1.
Add a proper zero-check to avoid it.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
[PG: in mainline, 21268961d3 rewrites and creates alc_mux_select, but the
code that needed the check still existed prior to that in alc_mux_enum_put]
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---
sound/pci/hda/patch_realtek.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/sound/pci/hda/patch_realtek.c b/sound/pci/hda/patch_realtek.c
index 94f1a80..28118fd 100644
--- a/sound/pci/hda/patch_realtek.c
+++ b/sound/pci/hda/patch_realtek.c
@@ -444,6 +444,8 @@ static int alc_mux_enum_put(struct snd_kcontrol *kcontrol,
imux = &spec->input_mux[mux_idx];
if (!imux->num_items && mux_idx > 0)
imux = &spec->input_mux[0];
+ if (!imux->num_items)
+ return 0;

type = get_wcaps_type(get_wcaps(codec, nid));
if (type == AC_WID_AUD_MIX) {
--
1.7.12.1