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Commit d513202e authored by Clemens Ladisch's avatar Clemens Ladisch Committed by Takashi Iwai
Browse files

[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: default avatarClemens Ladisch <clemens@ladisch.de>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent ee47fd12

sound/usb/usbaudio.c

+36 −2
Original line number Diff line number Diff line
@@ -479,6 +479,33 @@ static int retire_playback_sync_urb_hs(struct snd_usb_substream *subs, 
	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 @@ static void init_substream(struct snd_usb_stream *as, int stream, struct audiofo 
	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);