[ 047/136 ] ALSA: usb: Add quirk for 192KHz recording on E-Mu devices

Steven Rostedt
2013-05-18T02:17:10Z

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3.6.11.4 stable review patch.
If anyone has any objections, please let me know.

------------------

From: Calvin Owens <jcalvinowens@gmail.com>

[ Upstream commit 1539d4f82ad534431cc67935e8e442ccf107d17d ]

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>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
sound/usb/card.h | 1 +
sound/usb/pcm.c | 2 +-
sound/usb/quirks.c | 1 +
sound/usb/stream.c | 1 +
4 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/sound/usb/card.h b/sound/usb/card.h
index 6e262c5..48aabb6 100644
--- a/sound/usb/card.h
+++ b/sound/usb/card.h
@@ -112,6 +112,7 @@ 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 */

diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index 90731af..cbaecce 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -1017,7 +1017,7 @@ 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;
diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c
index 213ecad..2c22adf 100644
--- a/sound/usb/quirks.c
+++ b/sound/usb/quirks.c
@@ -746,6 +746,7 @@ 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,
diff --git a/sound/usb/stream.c b/sound/usb/stream.c
index e3c9b66..1891e49b 100644
--- a/sound/usb/stream.c
+++ b/sound/usb/stream.c
@@ -91,6 +91,7 @@ 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);

--
1.7.10.4