From 98e89f606c38a310a20342f90e0c453e6afadf18 Mon Sep 17 00:00:00 2001 From: "John S. Gruber" Date: Sun, 27 Dec 2009 12:19:58 -0500 Subject: ALSA: usb-audio: relax urb data align. restriction HVR-950Q and HVR-850 only Addressing audio quality problem. In sound/usb/usbaudio.c, for the Hauppage HVR-950Q and HVR-850 only, change retire_capture_urb to allow transfers on audio sub-slot boundaries rather than audio slots boundaries. With these devices the left and right channel samples can be split between two different urbs. Throwing away extra channel samples causes a sound quality problem for stereo streams as the left and right channels are swapped repeatedly, perhaps many times per second. Urbs unaligned on sub-slot boundaries are still truncated to the next lowest stride (audio slot) to retain synchronization on samples even though left/right channel synchronization may be lost in this case. Detect the quirk using a case statement in snd_usb_audio_probe. BugLink: https://bugs.launchpad.net/ubuntu/+bug/495745 Signed-off-by: John S. Gruber Signed-off-by: Takashi Iwai --- sound/usb/usbaudio.h | 1 + 1 file changed, 1 insertion(+) (limited to 'sound/usb/usbaudio.h') diff --git a/sound/usb/usbaudio.h b/sound/usb/usbaudio.h index 152216738cce..d180554b81f0 100644 --- a/sound/usb/usbaudio.h +++ b/sound/usb/usbaudio.h @@ -125,6 +125,7 @@ struct snd_usb_audio { struct snd_card *card; u32 usb_id; int shutdown; + unsigned int txfr_quirk:1; /* Subframe boundaries on transfers */ int num_interfaces; int num_suspended_intf; -- cgit