At least some USB devices use (MSB-aligned) audio format larger than the actual resolution of the device. In order to expose the actual device resolution (bBitResolution), add extra field to the procfs stream info interface.
Signed-off-by: Jussi Laako jussi@sonarnerd.net --- sound/usb/card.h | 1 + sound/usb/format.c | 2 ++ sound/usb/proc.c | 1 + 3 files changed, 4 insertions(+)
diff --git a/sound/usb/card.h b/sound/usb/card.h index ac785d15ced4..d9bb2c4a3bd9 100644 --- a/sound/usb/card.h +++ b/sound/usb/card.h @@ -14,6 +14,7 @@ struct audioformat { u64 formats; /* ALSA format bits */ unsigned int channels; /* # channels */ unsigned int fmt_type; /* USB audio format type (1-3) */ + unsigned int fmt_bits; /* number of significant bits */ unsigned int frame_size; /* samples per frame for non-audio */ int iface; /* interface number */ unsigned char altsetting; /* corresponding alternate setting */ diff --git a/sound/usb/format.c b/sound/usb/format.c index fd13ac11b136..d5b7cbcc2956 100644 --- a/sound/usb/format.c +++ b/sound/usb/format.c @@ -87,6 +87,8 @@ static u64 parse_audio_format_i_type(struct snd_usb_audio *chip, } }
+ fp->fmt_bits = (unsigned int) sample_width; + if ((pcm_formats == 0) && (format == 0 || format == (1 << UAC_FORMAT_TYPE_I_UNDEFINED))) { /* some devices don't define this correctly... */ diff --git a/sound/usb/proc.c b/sound/usb/proc.c index e80c9d0749c9..ef9190530fd2 100644 --- a/sound/usb/proc.c +++ b/sound/usb/proc.c @@ -109,6 +109,7 @@ static void proc_dump_substream_formats(struct snd_usb_substream *subs, struct s if (subs->speed != USB_SPEED_FULL) snd_iprintf(buffer, " Data packet interval: %d us\n", 125 * (1 << fp->datainterval)); + snd_iprintf(buffer, " Bits: %d\n", fp->fmt_bits); // snd_iprintf(buffer, " Max Packet Size = %d\n", fp->maxpacksize); // snd_iprintf(buffer, " EP Attribute = %#x\n", fp->attributes); }