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Add support for adjusting the hardware buffering delay for USB audio.

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Requested by:	Goran Mekic <meka@tilda.center>
MFC after:	1 week
This commit is contained in:
hselasky 2016-10-19 18:45:06 +00:00
parent 689aef672a
commit 981035660d
1 changed files with 30 additions and 5 deletions
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35
sys/dev/sound/usb/uaudio.c
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@ -95,6 +95,7 @@ __FBSDID("$FreeBSD$");
static int uaudio_default_rate = 0; /* use rate list */
static int uaudio_default_bits = 32;
static int uaudio_default_channels = 0; /* use default */
static int uaudio_buffer_ms = 8;
#ifdef USB_DEBUG
static int uaudio_debug = 0;
@ -109,9 +110,32 @@ SYSCTL_INT(_hw_usb_uaudio, OID_AUTO, default_bits, CTLFLAG_RWTUN,
&uaudio_default_bits, 0, "uaudio default sample bits");
SYSCTL_INT(_hw_usb_uaudio, OID_AUTO, default_channels, CTLFLAG_RWTUN,
&uaudio_default_channels, 0, "uaudio default sample channels");
static int
uaudio_buffer_ms_sysctl(SYSCTL_HANDLER_ARGS)
{
int err, val;
val = uaudio_buffer_ms;
err = sysctl_handle_int(oidp, &val, 0, req);
if (err != 0 || req->newptr == NULL || val == uaudio_buffer_ms)
return (err);
if (val > 8)
val = 8;
else if (val < 2)
val = 2;
uaudio_buffer_ms = val;
return (0);
}
SYSCTL_PROC(_hw_usb_uaudio, OID_AUTO, buffer_ms, CTLTYPE_INT | CTLFLAG_RWTUN,
0, sizeof(int), uaudio_buffer_ms_sysctl, "I",
"uaudio buffering delay from 2ms to 8ms");
#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 */
@ -1278,10 +1302,10 @@ uaudio_configure_msg_sub(struct uaudio_softc *sc,
if (fps < 8000) {
/* FULL speed USB */
frames = 8;
frames = uaudio_buffer_ms;
} else {
/* HIGH speed USB */
frames = UAUDIO_NFRAMES;
frames = uaudio_buffer_ms * 8;
}
fps_shift = usbd_xfer_get_fps_shift(chan->xfer[0]);
@ -2158,8 +2182,9 @@ tr_setup:
}
/* start the SYNC transfer one time per second, if any */
if (++(ch->intr_counter) >= UAUDIO_IRQS) {
ch->intr_counter = 0;
ch->intr_counter += ch->intr_frames;
if (ch->intr_counter >= ch->frames_per_second) {
ch->intr_counter -= ch->frames_per_second;
usbd_transfer_start(ch->xfer[UAUDIO_NCHANBUFS]);
}