[PATCH v35 10/31] ALSA: usb-audio: Save UAC sample size information
From: Wesley Cheng <hidden>
Date: 2025-02-19 00:48:27
Also in:
linux-arm-msm, linux-devicetree, linux-input, linux-sound, linux-usb, lkml
Subsystem:
sound, the rest · Maintainers:
Jaroslav Kysela, Takashi Iwai, Linus Torvalds
Within the UAC descriptor, there is information describing the size of a sample (bSubframeSize/bSubslotSize) and the number of relevant bits (bBitResolution). Currently, fmt_bits carries only the bit resolution, however, some offloading entities may also require the overall size of the sample. Save this information in a separate parameter, as depending on the UAC format type, the sample size can not easily be decoded from other existing parameters. Reviewed-by: Pierre-Louis Bossart <redacted> Signed-off-by: Wesley Cheng <redacted> --- sound/usb/card.h | 1 + sound/usb/format.c | 1 + 2 files changed, 2 insertions(+)
diff --git a/sound/usb/card.h b/sound/usb/card.h
index 4f4f3f39b7fa..b65163c60176 100644
--- a/sound/usb/card.h
+++ b/sound/usb/card.h@@ -15,6 +15,7 @@ struct audioformat { unsigned int channels; /* # channels */ unsigned int fmt_type; /* USB audio format type (1-3) */ unsigned int fmt_bits; /* number of significant bits */ + unsigned int fmt_sz; /* overall audio sub frame/slot size */ unsigned int frame_size; /* samples per frame for non-audio */ unsigned char iface; /* interface number */ unsigned char altsetting; /* corresponding alternate setting */
diff --git a/sound/usb/format.c b/sound/usb/format.c
index 6049d957694c..f66449e5d634 100644
--- a/sound/usb/format.c
+++ b/sound/usb/format.c@@ -85,6 +85,7 @@ static u64 parse_audio_format_i_type(struct snd_usb_audio *chip, } fp->fmt_bits = sample_width; + fp->fmt_sz = sample_bytes; if ((pcm_formats == 0) && (format == 0 || format == BIT(UAC_FORMAT_TYPE_I_UNDEFINED))) {