Unfortunately, none of the UAC standards provides a way to identify DSD (Direct Stream Digital) formats. Hence, this patch adds a quirks handler to identify USB interfaces that are capable of handling DSD.
If that quirks handler returns /true/, the PCM formats will be augmented by SNDRV_PCM_FMTBIT_DSD_{U8_U16}, depending on the parsed sample_bytes.
Signed-off-by: Daniel Mack zonque@gmail.com --- sound/usb/format.c | 19 +++++++++++++++++++ sound/usb/quirks.c | 8 ++++++++ sound/usb/quirks.h | 3 +++ 3 files changed, 30 insertions(+)
diff --git a/sound/usb/format.c b/sound/usb/format.c index a695caf..e4c8610 100644 --- a/sound/usb/format.c +++ b/sound/usb/format.c @@ -136,6 +136,25 @@ static u64 parse_audio_format_i_type(struct snd_usb_audio *chip, snd_printk(KERN_INFO "%d:%u:%d : unsupported format bits %#x\n", chip->dev->devnum, fp->iface, fp->altsetting, format); } + + /* + * DSD has no designated specifiers in the USB audio spec, so we have + * to rely on a quirks list. + */ + if (snd_usb_interface_is_dsd(chip->dev, fp->iface, fp->altsetting)) { + switch (sample_bytes) { + case 1: + pcm_formats |= SNDRV_PCM_FMTBIT_DSD_U8; + break; + case 2: + pcm_formats |= SNDRV_PCM_FMTBIT_DSD_U16; + break; + default: + snd_printk(KERN_INFO "%d:%u:%d : unsupported DSD sample bitwidth %d\n", + chip->dev->devnum, fp->iface, fp->altsetting, sample_width); + } + } + return pcm_formats; }
diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c index a2ac004..9d7e95c 100644 --- a/sound/usb/quirks.c +++ b/sound/usb/quirks.c @@ -905,3 +905,11 @@ void snd_usb_ctl_msg_quirk(struct usb_device *dev, unsigned int pipe, mdelay(20); }
+bool snd_usb_interface_is_dsd(struct usb_device *dev, + int interface, int alt_no) +{ + if ((le16_to_cpu(dev->descriptor.idVendor) == 0x23ba) && alt_no > 1) + return true; + + return false; +} diff --git a/sound/usb/quirks.h b/sound/usb/quirks.h index 0ca9e91..a777ef0 100644 --- a/sound/usb/quirks.h +++ b/sound/usb/quirks.h @@ -30,4 +30,7 @@ void snd_usb_ctl_msg_quirk(struct usb_device *dev, unsigned int pipe, __u8 request, __u8 requesttype, __u16 value, __u16 index, void *data, __u16 size);
+bool snd_usb_interface_is_dsd(struct usb_device *dev, + int interface, int alt_no); + #endif /* __USBAUDIO_QUIRKS_H */