From 3a572d94bcff98a14c94fe686881a169a26f3fca Mon Sep 17 00:00:00 2001
From: Jussi Laako <jussi@sonarnerd.net>
Date: Wed, 13 Jun 2018 01:43:01 +0300
Subject: [PATCH] ALSA: usb-audio: Add native DSD support for Mytek DACs
Git-commit: 3a572d94bcff98a14c94fe686881a169a26f3fca
Patch-mainline: v4.18-rc1
References: bsc#1051510
Add new mostly generic code with Mytek VID to support native DSD mode.
This implementation should be easier to maintain when manufacturers
release new products.
Signed-off-by: Jussi Laako <jussi@sonarnerd.net>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
sound/usb/card.h | 1 +
sound/usb/format.c | 5 ++++-
sound/usb/quirks.c | 13 +++++++++++++
3 files changed, 18 insertions(+), 1 deletion(-)
--- a/sound/usb/card.h
+++ b/sound/usb/card.h
@@ -31,6 +31,7 @@ struct audioformat {
struct snd_pcm_chmap_elem *chmap; /* (optional) channel map */
bool dsd_dop; /* add DOP headers in case of DSD samples */
bool dsd_bitrev; /* reverse the bits of each DSD sample */
+ bool dsd_raw; /* altsetting is raw DSD */
};
struct snd_usb_substream;
--- a/sound/usb/format.c
+++ b/sound/usb/format.c
@@ -63,8 +63,11 @@ static u64 parse_audio_format_i_type(str
sample_width = fmt->bBitResolution;
sample_bytes = fmt->bSubslotSize;
- if (format & UAC2_FORMAT_TYPE_I_RAW_DATA)
+ if (format & UAC2_FORMAT_TYPE_I_RAW_DATA) {
pcm_formats |= SNDRV_PCM_FMTBIT_SPECIAL;
+ /* flag potentially raw DSD capable altsettings */
+ fp->dsd_raw = true;
+ }
format <<= 1;
break;
--- a/sound/usb/quirks.c
+++ b/sound/usb/quirks.c
@@ -1444,6 +1444,19 @@ u64 snd_usb_interface_dsd_format_quirks(
return SNDRV_PCM_FMTBIT_DSD_U32_BE;
}
+ /* Mostly generic method to detect many DSD-capable implementations -
+ * from XMOS/Thesycon
+ */
+ switch (USB_ID_VENDOR(chip->usb_id)) {
+ case 0x25ce: /* Mytek devices */
+ if (fp->dsd_raw)
+ return SNDRV_PCM_FMTBIT_DSD_U32_BE;
+ break;
+ default:
+ break;
+
+ }
+
return 0;
}