| Message ID | 20190217221721.6396-1-jussi@sonarnerd.net (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | ALSA: usb-audio: Expose sample resolution through proc interface | expand |
On 2/18/19 10:40 AM, Takashi Iwai wrote: > > The code change looks but, just some minor issues: > > Please use tabs. checkpatch will catch such a problem, so please run > it at the next time before submission. > > I applied the patch with these fixed locally. OK, thanks! Will do! Ultimately I would like to get the sample resolution for example through snd_pcm_hw_params_get_sbits(), but I didn't find a nice way to get this information to the ALSA API without lot of changes all over the place, or alternatively introducing a new sample format which I think is not a good idea in this case. I can parse the stream info from proc though, so it is not so much issue. Best regards, - Jussi
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); }
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(+)