svn commit: r340248 - head/sys/dev/sound/usb
Hans Petter Selasky
hselasky at FreeBSD.org
Thu Nov 8 12:46:48 UTC 2018
Author: hselasky
Date: Thu Nov 8 12:46:47 2018
New Revision: 340248
URL: https://svnweb.freebsd.org/changeset/base/340248
Log:
Don't read the USB audio sync endpoint when we don't use it to save
isochronous bandwidth.
MFC after: 3 days
Sponsored by: Mellanox Technologies
Modified:
head/sys/dev/sound/usb/uaudio.c
Modified: head/sys/dev/sound/usb/uaudio.c
==============================================================================
--- head/sys/dev/sound/usb/uaudio.c Thu Nov 8 12:45:28 2018 (r340247)
+++ head/sys/dev/sound/usb/uaudio.c Thu Nov 8 12:46:47 2018 (r340248)
@@ -100,7 +100,7 @@ static int uaudio_default_channels = 0; /* use defaul
static int uaudio_buffer_ms = 8;
#ifdef USB_DEBUG
-static int uaudio_debug = 0;
+static int uaudio_debug;
static SYSCTL_NODE(_hw_usb, OID_AUTO, uaudio, CTLFLAG_RW, 0, "USB uaudio");
@@ -136,6 +136,8 @@ uaudio_buffer_ms_sysctl(SYSCTL_HANDLER_ARGS)
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");
+#else
+#define uaudio_debug 0
#endif
#define UAUDIO_NFRAMES 64 /* must be factor of 8 due HS-USB */
@@ -2161,6 +2163,14 @@ uaudio_chan_play_sync_callback(struct usb_xfer *xfer,
break;
case USB_ST_SETUP:
+ /*
+ * Check if the recording stream can be used as a
+ * source of jitter information to save some
+ * isochronous bandwidth:
+ */
+ if (ch->priv_sc->sc_rec_chan.num_alt != 0 &&
+ uaudio_debug == 0)
+ break;
usbd_xfer_set_frames(xfer, 1);
usbd_xfer_set_frame_len(xfer, 0, usbd_xfer_max_framelen(xfer));
usbd_transfer_submit(xfer);
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