Author: hselasky
Date: Fri Feb 13 07:53:18 2015
New Revision: 278666
URL: https://svnweb.freebsd.org/changeset/base/278666
Log:
MFC r278503:
Revert r274918 and make a better solution. Poll the synchronisation
endpoint less frequently to make the sample rate adjustment more
accurate. This should resolve problems with the DN32-USB module for
Midas audio systems and possibly other similar products from Klark
Teknik.
Modified:
stable/8/sys/dev/sound/usb/uaudio.c
Directory Properties:
stable/8/sys/ (props changed)
stable/8/sys/dev/ (props changed)
stable/8/sys/dev/sound/ (props changed)
stable/8/sys/dev/sound/usb/ (props changed)
Modified: stable/8/sys/dev/sound/usb/uaudio.c
==============================================================================
--- stable/8/sys/dev/sound/usb/uaudio.c Fri Feb 13 07:52:12 2015
(r278665)
+++ stable/8/sys/dev/sound/usb/uaudio.c Fri Feb 13 07:53:18 2015
(r278666)
@@ -117,6 +117,7 @@ SYSCTL_INT(_hw_usb_uaudio, OID_AUTO, def
&uaudio_default_channels, 0, "uaudio default sample channels");
#endif
+#define UAUDIO_IRQS (8000 / UAUDIO_NFRAMES) /* interrupts per
second */
#define UAUDIO_NFRAMES 64 /* must be factor of 8 due
HS-USB */
#define UAUDIO_NCHANBUFS 2 /* number of outstanding
request */
#define UAUDIO_RECURSE_LIMIT 255 /* rounds */
@@ -195,7 +196,6 @@ struct uaudio_chan_alt {
uint8_t iface_index;
uint8_t iface_alt_index;
uint8_t channels;
- uint8_t enable_sync;
};
struct uaudio_chan {
@@ -232,11 +232,12 @@ struct uaudio_chan {
#define CHAN_OP_STOP 2
#define CHAN_OP_DRAIN 3
- uint8_t last_sync_time;
- uint8_t last_sync_state;
-#define UAUDIO_SYNC_NONE 0
-#define UAUDIO_SYNC_MORE 1
-#define UAUDIO_SYNC_LESS 2
+ /* USB audio feedback endpoint state */
+ struct {
+ uint16_t time; /* I/O interrupt count */
+ int16_t constant; /* sample rate adjustment in Hz */
+ int16_t remainder; /* current remainder */
+ } feedback;
};
#define UMIDI_EMB_JACK_MAX 16 /* units */
@@ -1805,14 +1806,6 @@ uaudio_chan_fill_info_sub(struct uaudio_
chan_alt->iface_index = curidx;
chan_alt->iface_alt_index = alt_index;
- if (UEP_HAS_SYNCADDR(ed1) && ed1->bSynchAddress != 0) {
- DPRINTF("Sync endpoint will be used, if present\n");
- chan_alt->enable_sync = 1;
- } else {
- DPRINTF("Sync endpoint will not be used\n");
- chan_alt->enable_sync = 0;
- }
-
usbd_set_parent_iface(sc->sc_udev, curidx,
sc->sc_mixer_iface_index);
@@ -2022,29 +2015,44 @@ uaudio_chan_play_sync_callback(struct us
if (temp == 0)
break;
- /* correctly scale value */
-
- temp = (temp * 125ULL) - 64;
+ temp *= 125ULL;
/* auto adjust */
-
while (temp < (sample_rate - (sample_rate / 4)))
temp *= 2;
-
+
while (temp > (sample_rate + (sample_rate / 2)))
temp /= 2;
- /* compare */
+ /*
+ * Some USB audio devices only report a sample rate
+ * different from the nominal one when they want one
+ * more or less sample. Make sure we catch this case
+ * by pulling the sample rate offset slowly towards
+ * zero if the reported value is equal to the sample
+ * rate.
+ */
+ if (temp > sample_rate)
+ ch->feedback.constant += 1;
+ else if (temp < sample_rate)
+ ch->feedback.constant -= 1;
+ else if (ch->feedback.constant > 0)
+ ch->feedback.constant--;
+ else if (ch->feedback.constant < 0)
+ ch->feedback.constant++;
- DPRINTF("Comparing %d < %d\n",
- (int)temp, (int)sample_rate);
+ DPRINTF("Comparing %d Hz :: %d Hz :: %d samples drift\n",
+ (int)temp, (int)sample_rate, (int)ch->feedback.constant);
- if (temp == sample_rate)
- ch->last_sync_state = UAUDIO_SYNC_NONE;
- else if (temp > sample_rate)
- ch->last_sync_state = UAUDIO_SYNC_MORE;
- else
- ch->last_sync_state = UAUDIO_SYNC_LESS;
+ /*
+ * Range check sync constant. We cannot change the
+ * number of samples per second by more than the value
+ * defined by "UAUDIO_IRQS":
+ */
+ if (ch->feedback.constant > UAUDIO_IRQS)
+ ch->feedback.constant = UAUDIO_IRQS;
+ else if (ch->feedback.constant < -UAUDIO_IRQS)
+ ch->feedback.constant = -UAUDIO_IRQS;
break;
case USB_ST_SETUP:
@@ -2088,10 +2096,10 @@ tr_transferred:
}
chn_intr(ch->pcm_ch);
- /* start SYNC transfer, if any */
- if (ch->usb_alt[ch->cur_alt].enable_sync != 0) {
- if ((ch->last_sync_time++ & 7) == 0)
- usbd_transfer_start(ch->xfer[UAUDIO_NCHANBUFS]);
+ /* start the SYNC transfer one time per second, if any */
+ if (++(ch->feedback.time) >= UAUDIO_IRQS) {
+ ch->feedback.time = 0;
+ usbd_transfer_start(ch->xfer[UAUDIO_NCHANBUFS]);
}
case USB_ST_SETUP:
@@ -2126,21 +2134,22 @@ tr_transferred:
}
if (n == (blockcount - 1)) {
- switch (ch->last_sync_state) {
- case UAUDIO_SYNC_MORE:
+ /*
+ * Update sync remainder and check if
+ * we should transmit more or less
+ * data:
+ */
+ ch->feedback.remainder += ch->feedback.constant;
+ if (ch->feedback.remainder >= UAUDIO_IRQS) {
+ ch->feedback.remainder -= UAUDIO_IRQS;
DPRINTFN(6, "sending one sample
more\n");
if ((frame_len + sample_size) <= mfl)
frame_len += sample_size;
- ch->last_sync_state = UAUDIO_SYNC_NONE;
- break;
- case UAUDIO_SYNC_LESS:
+ } else if (ch->feedback.remainder <=
-UAUDIO_IRQS) {
+ ch->feedback.remainder += UAUDIO_IRQS;
DPRINTFN(6, "sending one sample
less\n");
if (frame_len >= sample_size)
frame_len -= sample_size;
- ch->last_sync_state = UAUDIO_SYNC_NONE;
- break;
- default:
- break;
}
}
@@ -2458,6 +2467,9 @@ uaudio_chan_start(struct uaudio_chan *ch
}
usb_proc_explore_unlock(sc->sc_udev);
+ /* reset feedback endpoint state */
+ memset(&ch->feedback, 0, sizeof(ch->feedback));
+
if (do_start) {
usbd_transfer_start(ch->xfer[0]);
usbd_transfer_start(ch->xfer[1]);
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