[ALSA] usbaudio - Fix Oops with broken usb descriptors

This is a patch for ALSA Bug #2724. Some webcams provide bogus
settings with no valid rates. With this patch those are skipped.

Signed-off-by: Gregor Jasny <gjasny@web.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>

1 files changed, 6 insertions, 0 deletions

diff --git a/sound/usb/usbaudio.c b/sound/usb/usbaudio.c
index de680d095e94..56e42b88addf 100644
--- a/sound/usb/usbaudio.c
+++ b/sound/usb/usbaudio.c
@@ -2463,6 +2463,7 @@ static int parse_audio_format_rates(struct snd_usb_audio *chip, struct audioform
                  * build the rate table and bitmap flags
                  */
                 int r, idx, c;
+                unsigned int nonzero_rates = 0;
                 /* this table corresponds to the SNDRV_PCM_RATE_XXX bit */
                 static unsigned int conv_rates[] = {
                         5512, 8000, 11025, 16000, 22050, 32000, 44100, 48000,
@@ -2485,6 +2486,7 @@ static int parse_audio_format_rates(struct snd_usb_audio *chip, struct audioform
                             fp->altsetting == 5 && fp->maxpacksize == 392)
                                 rate = 96000;
                         fp->rate_table[r] = rate;
+                        nonzero_rates |= rate;
                         if (rate < fp->rate_min)
                                 fp->rate_min = rate;
                         else if (rate > fp->rate_max)
@@ -2500,6 +2502,10 @@ static int parse_audio_format_rates(struct snd_usb_audio *chip, struct audioform
                         if (!found)
                                 fp->needs_knot = 1;
                 }
+                if (!nonzero_rates) {
+                        hwc_debug("All rates were zero. Skipping format!\n");
+                        return -1;
+                }
                 if (fp->needs_knot)
                         fp->rates |= SNDRV_PCM_RATE_KNOT;
         } else {