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Commit 1539d4f8 authored by Calvin Owens's avatar Calvin Owens Committed by Takashi Iwai
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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: default avatarCalvin Owens <jcalvinowens@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent b26b5116

sound/usb/card.h

+1 −0
Original line number Diff line number Diff line
@@ -116,6 +116,7 @@ struct snd_usb_substream { 
	unsigned int altset_idx;     /* USB data format: index of alternate setting */

	unsigned int txfr_quirk:1;	/* allow sub-frame alignment */

	unsigned int fmt_type;		/* USB audio format type (1-3) */

	unsigned int pkt_offset_adj;	/* Bytes to drop from beginning of packets (for non-compliant devices) */



	unsigned int running: 1;	/* running status */

sound/usb/pcm.c

+1 −1
Original line number Diff line number Diff line
@@ -1162,7 +1162,7 @@ static void retire_capture_urb(struct snd_usb_substream *subs, 
	stride = runtime->frame_bits >> 3;



	for (i = 0; i < urb->number_of_packets; i++) {

		cp = (unsigned char *)urb->transfer_buffer + urb->iso_frame_desc[i].offset;

		cp = (unsigned char *)urb->transfer_buffer + urb->iso_frame_desc[i].offset + subs->pkt_offset_adj;

		if (urb->iso_frame_desc[i].status && printk_ratelimit()) {

			snd_printdd(KERN_ERR "frame %d active: %d\n", i, urb->iso_frame_desc[i].status);

			// continue;

sound/usb/quirks.c

+1 −0
Original line number Diff line number Diff line
@@ -854,6 +854,7 @@ static void set_format_emu_quirk(struct snd_usb_substream *subs, 
		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,

sound/usb/stream.c

+1 −0
Original line number Diff line number Diff line
@@ -93,6 +93,7 @@ static void snd_usb_init_substream(struct snd_usb_stream *as, 
	subs->dev = as->chip->dev;

	subs->txfr_quirk = as->chip->txfr_quirk;

	subs->speed = snd_usb_get_speed(subs->dev);

	subs->pkt_offset_adj = 0;



	snd_usb_set_pcm_ops(as->pcm, stream);