[ALSA] usb-audio: add workaround for broken E-Mu frequency feedback
Add a workaround for the feedback pipe of E-Mu 0202/0404 USB devices
that reports the number of samples per packet instead of the number of
samples per microframe.
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/usb/usbaudio.c b/sound/usb/usbaudio.c
index 8fa9356..675672f 100644
--- a/sound/usb/usbaudio.c
+++ b/sound/usb/usbaudio.c
@@ -479,6 +479,33 @@
return 0;
}
+/*
+ * process after E-Mu 0202/0404 high speed playback sync complete
+ *
+ * These devices return the number of samples per packet instead of the number
+ * of samples per microframe.
+ */
+static int retire_playback_sync_urb_hs_emu(struct snd_usb_substream *subs,
+ struct snd_pcm_runtime *runtime,
+ struct urb *urb)
+{
+ unsigned int f;
+ unsigned long flags;
+
+ if (urb->iso_frame_desc[0].status == 0 &&
+ urb->iso_frame_desc[0].actual_length == 4) {
+ f = combine_quad((u8*)urb->transfer_buffer) & 0x0fffffff;
+ f >>= subs->datainterval;
+ if (f >= subs->freqn - subs->freqn / 8 && f <= subs->freqmax) {
+ spin_lock_irqsave(&subs->lock, flags);
+ subs->freqm = f;
+ spin_unlock_irqrestore(&subs->lock, flags);
+ }
+ }
+
+ return 0;
+}
+
/* determine the number of frames in the next packet */
static int snd_usb_audio_next_packet_size(struct snd_usb_substream *subs)
{
@@ -2219,10 +2246,17 @@
subs->stream = as;
subs->direction = stream;
subs->dev = as->chip->dev;
- if (snd_usb_get_speed(subs->dev) == USB_SPEED_FULL)
+ if (snd_usb_get_speed(subs->dev) == USB_SPEED_FULL) {
subs->ops = audio_urb_ops[stream];
- else
+ } else {
subs->ops = audio_urb_ops_high_speed[stream];
+ switch (as->chip->usb_id) {
+ case USB_ID(0x041e, 0x3f02): /* E-Mu 0202 USB */
+ case USB_ID(0x041e, 0x3f04): /* E-Mu 0404 USB */
+ subs->ops.retire_sync = retire_playback_sync_urb_hs_emu;
+ break;
+ }
+ }
snd_pcm_set_ops(as->pcm, stream,
stream == SNDRV_PCM_STREAM_PLAYBACK ?
&snd_usb_playback_ops : &snd_usb_capture_ops);
