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authorCalvin Owens <jcalvinowens@gmail.com>2013-04-12 22:33:59 -0500
committerTakashi Iwai <tiwai@suse.de>2013-04-13 10:58:03 +0200
commit1539d4f82ad534431cc67935e8e442ccf107d17d (patch)
treeedb34bea8a89d757f14bbf099329285c036f7279 /sound/usb/card.h
parentb26b51166848758d740ab638fc27789228a51c97 (diff)
downloadlwn-1539d4f82ad534431cc67935e8e442ccf107d17d.tar.gz
lwn-1539d4f82ad534431cc67935e8e442ccf107d17d.zip
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>
Diffstat (limited to 'sound/usb/card.h')
-rw-r--r--sound/usb/card.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/sound/usb/card.h b/sound/usb/card.h
index 8a751b4887ea..d32ea411545a 100644
--- a/sound/usb/card.h
+++ b/sound/usb/card.h
@@ -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 */