diff options
| author | Alexey Fisher <bug-track@fisher-privat.net> | 2011-03-10 14:53:38 +0100 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2011-03-10 16:47:56 +0100 |
| commit | 80acefff3bc7bd53d46c16c683ab66c0ece20810 (patch) | |
| tree | 85078478ccf6f934688dbda6b9056a9867bba6cd /sound | |
| parent | 848669da3a92fa6ab815e0517af3294afb3ea928 (diff) | |
| download | lwn-80acefff3bc7bd53d46c16c683ab66c0ece20810.tar.gz lwn-80acefff3bc7bd53d46c16c683ab66c0ece20810.zip | |
ALSA: usb-audio - Add volume range check and warn if it too big
Signed-off-by: Alexey Fisher <bug-track@fisher-privat.net>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound')
| -rw-r--r-- | sound/usb/mixer.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c index 7df89b3d7ded..3e3116c5bc52 100644 --- a/sound/usb/mixer.c +++ b/sound/usb/mixer.c @@ -987,6 +987,7 @@ static void build_feature_ctl(struct mixer_build *state, void *raw_desc, struct snd_kcontrol *kctl; struct usb_mixer_elem_info *cval; const struct usbmix_name_map *map; + unsigned int range; control++; /* change from zero-based to 1-based value */ @@ -1136,6 +1137,21 @@ static void build_feature_ctl(struct mixer_build *state, void *raw_desc, } + range = (cval->max - cval->min) / cval->res; + /* Are there devices with volume range more than 255? I use a bit more + * to be sure. 384 is a resolution magic number found on Logitech + * devices. It will definitively catch all buggy Logitech devices. + */ + if (range > 384) { + snd_printk(KERN_WARNING "usb_audio: Warning! Unlikely big " + "volume range (=%u), cval->res is probably wrong.", + range); + snd_printk(KERN_WARNING "usb_audio: [%d] FU [%s] ch = %d, " + "val = %d/%d/%d", cval->id, + kctl->id.name, cval->channels, + cval->min, cval->max, cval->res); + } + snd_printdd(KERN_INFO "[%d] FU [%s] ch = %d, val = %d/%d/%d\n", cval->id, kctl->id.name, cval->channels, cval->min, cval->max, cval->res); add_control_to_empty(state, kctl); |