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authorJohn S. Gruber <JohnSGruber@gmail.com>2009-12-27 12:19:58 -0500
committerTakashi Iwai <tiwai@suse.de>2009-12-28 12:30:41 +0100
commit98e89f606c38a310a20342f90e0c453e6afadf18 (patch)
treeed5a677157cf5bdd781c04e986813f112c6bf72c
parentadc8d31326c32a2a1e145ab80accbc3c6570b117 (diff)
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 <JohnSGruber@gmail.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
-rw-r--r--sound/usb/usbaudio.c31
-rw-r--r--sound/usb/usbaudio.h1
2 files changed, 30 insertions, 2 deletions
diff --git a/sound/usb/usbaudio.c b/sound/usb/usbaudio.c
index 8fcb5d5a94b..617515f6ec7 100644
--- a/sound/usb/usbaudio.c
+++ b/sound/usb/usbaudio.c
@@ -169,6 +169,7 @@ struct snd_usb_substream {
unsigned int curpacksize; /* current packet size in bytes (for capture) */
unsigned int curframesize; /* current packet size in frames (for capture) */
unsigned int fill_max: 1; /* fill max packet size always */
+ unsigned int txfr_quirk:1; /* allow sub-frame alignment */
unsigned int fmt_type; /* USB audio format type (1-3) */
unsigned int running: 1; /* running status */
@@ -353,14 +354,25 @@ static int retire_capture_urb(struct snd_usb_substream *subs,
snd_printd(KERN_ERR "frame %d active: %d\n", i, urb->iso_frame_desc[i].status);
// continue;
}
- frames = urb->iso_frame_desc[i].actual_length / stride;
- bytes = frames * stride;
+ bytes = urb->iso_frame_desc[i].actual_length;
+ frames = bytes / stride;
+ if (!subs->txfr_quirk)
+ bytes = frames * stride;
+ if (bytes % (runtime->sample_bits >> 3) != 0) {
+#ifdef CONFIG_SND_DEBUG_VERBOSE
+ int oldbytes = bytes;
+#endif
+ bytes = frames * stride;
+ snd_printdd(KERN_ERR "Corrected urb data len. %d->%d\n",
+ oldbytes, bytes);
+ }
/* update the current pointer */
spin_lock_irqsave(&subs->lock, flags);
oldptr = subs->hwptr_done;
subs->hwptr_done += bytes;
if (subs->hwptr_done >= runtime->buffer_size * stride)
subs->hwptr_done -= runtime->buffer_size * stride;
+ frames = (bytes + (oldptr % stride)) / stride;
subs->transfer_done += frames;
if (subs->transfer_done >= runtime->period_size) {
subs->transfer_done -= runtime->period_size;
@@ -2238,6 +2250,7 @@ static void init_substream(struct snd_usb_stream *as, int stream, struct audiofo
subs->stream = as;
subs->direction = stream;
subs->dev = as->chip->dev;
+ subs->txfr_quirk = as->chip->txfr_quirk;
if (snd_usb_get_speed(subs->dev) == USB_SPEED_FULL) {
subs->ops = audio_urb_ops[stream];
} else {
@@ -3618,6 +3631,20 @@ static void *snd_usb_audio_probe(struct usb_device *dev,
}
}
+ switch (chip->usb_id) {
+ case USB_ID(0x2040, 0x7200): /* Hauppage hvr950Q */
+ case USB_ID(0x2040, 0x7221): /* Hauppage hvr950Q */
+ case USB_ID(0x2040, 0x7222): /* Hauppage hvr950Q */
+ case USB_ID(0x2040, 0x7223): /* Hauppage hvr950Q */
+ case USB_ID(0x2040, 0x7224): /* Hauppage hvr950Q */
+ case USB_ID(0x2040, 0x7225): /* Hauppage hvr950Q */
+ case USB_ID(0x2040, 0x7230): /* Hauppage hvr850 */
+ case USB_ID(0x2040, 0x7250): /* Hauppage hvr950Q */
+ chip->txfr_quirk = 1;
+ break;
+ default:
+ chip->txfr_quirk = 0;
+ }
err = 1; /* continue */
if (quirk && quirk->ifnum != QUIRK_NO_INTERFACE) {
/* need some special handlings */
diff --git a/sound/usb/usbaudio.h b/sound/usb/usbaudio.h
index 152216738cc..d180554b81f 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;