Use the "bSubslotSize" and "bSubFrameSize" fields to obtain the actual

sample size. According to the USB audio frame format specification
from USB.org, the value in the "bBitResolution" field can be less than
the actual sample size, depending on the actual hardware, and should
not be used for this computation.

PR:		192755
MFC after:	1 week

1 files changed, 2 insertions, 13 deletions

diff --git a/sys/dev/sound/usb/uaudio.c b/sys/dev/sound/usb/uaudio.c
index 6c798cc..9d98a78 100644
--- a/sys/dev/sound/usb/uaudio.c
+++ b/sys/dev/sound/usb/uaudio.c
@@ -1659,21 +1659,10 @@ uaudio_chan_fill_info_sub(struct uaudio_softc *sc, struct usb_device *udev,
 		} else if (audio_rev >= UAUDIO_VERSION_20) {
 
 			uint32_t dwFormat;
-			uint8_t bSubslotSize;
 
 			dwFormat = UGETDW(asid.v2->bmFormats);
 			bChannels = asid.v2->bNrChannels;
-			bBitResolution = asf1d.v2->bBitResolution;
-			bSubslotSize = asf1d.v2->bSubslotSize;
-
-			/* Map 4-byte aligned 24-bit samples into 32-bit */
-			if (bBitResolution == 24 && bSubslotSize == 4)
-				bBitResolution = 32;
-
-			if (bBitResolution != (bSubslotSize * 8)) {
-				DPRINTF("Invalid bSubslotSize\n");
-				goto next_ep;
-			}
+			bBitResolution = asf1d.v2->bSubslotSize * 8;
 
 			if ((bChannels != channels) ||
 			    (bBitResolution != bit_resolution)) {
@@ -1720,7 +1709,7 @@ uaudio_chan_fill_info_sub(struct uaudio_softc *sc, struct usb_device *udev,
 
 			wFormat = UGETW(asid.v1->wFormatTag);
 			bChannels = UAUDIO_MAX_CHAN(asf1d.v1->bNrChannels);
-			bBitResolution = asf1d.v1->bBitResolution;
+			bBitResolution = asf1d.v1->bSubFrameSize * 8;
 
 			if (asf1d.v1->bSamFreqType == 0) {
 				DPRINTFN(16, "Sample rate: %d-%dHz\n",