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-rw-r--r--sound/usb/stream.c18
1 files changed, 13 insertions, 5 deletions
diff --git a/sound/usb/stream.c b/sound/usb/stream.c
index c4339f97226b..b43b6eec3227 100644
--- a/sound/usb/stream.c
+++ b/sound/usb/stream.c
@@ -281,8 +281,6 @@ static struct snd_pcm_chmap_elem *convert_chmap(int channels, unsigned int bits,
const unsigned int *maps;
int c;
- if (!bits)
- return NULL;
if (channels > ARRAY_SIZE(chmap->map))
return NULL;
@@ -293,9 +291,19 @@ static struct snd_pcm_chmap_elem *convert_chmap(int channels, unsigned int bits,
maps = protocol == UAC_VERSION_2 ? uac2_maps : uac1_maps;
chmap->channels = channels;
c = 0;
- for (; bits && *maps; maps++, bits >>= 1) {
- if (bits & 1)
- chmap->map[c++] = *maps;
+
+ if (bits) {
+ for (; bits && *maps; maps++, bits >>= 1)
+ if (bits & 1)
+ chmap->map[c++] = *maps;
+ } else {
+ /* If we're missing wChannelConfig, then guess something
+ to make sure the channel map is not skipped entirely */
+ if (channels == 1)
+ chmap->map[c++] = SNDRV_CHMAP_MONO;
+ else
+ for (; c < channels && *maps; maps++)
+ chmap->map[c++] = *maps;
}
for (; c < channels; c++)