ALSA: usb: Add quirk for 192KHz recording on E-Mu devices
When recording at 176.2KHz or 192Khz, the device adds a 32-bit length
header to the capture packets, which obviously needs to be ignored for
recording to work properly.
Userspace expected: L0 L1 L2 R0 R1 R2
...but actually got: R2 L0 L1 L2 R0 R1
Also, the last byte of the length header being interpreted as L0 of
the first sample caused spikes every 0.5ms, resulting in a loud 16KHz
tone (about the highest 'B' on a piano) being present throughout
captures.
Tested at all sample rates on an E-Mu 0404USB, and tested for
regressions on a generic USB headset.
Signed-off-by: Calvin Owens <jcalvinowens@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c
index 2927981..175fbb7 100644
--- a/sound/usb/quirks.c
+++ b/sound/usb/quirks.c
@@ -854,6 +854,7 @@
break;
}
snd_emuusb_set_samplerate(subs->stream->chip, emu_samplerate_id);
+ subs->pkt_offset_adj = (emu_samplerate_id >= EMU_QUIRK_SR_176400HZ) ? 4 : 0;
}
void snd_usb_set_format_quirk(struct snd_usb_substream *subs,