[PATCH] Remove stream pipe draining code for CXUSB D680 DMB

[David Wong <davidtlwong@xxxxxxxxx>]

CXUSB D680 DMB pipe draining code found to be problematic for new
kernels (eg. kernel 2.6.27 @ Ubuntu 8.10)

David T.L. Wong

diff -r 626c136ec221 linux/drivers/media/dvb/dvb-usb/cxusb.c
--- a/linux/drivers/media/dvb/dvb-usb/cxusb.c	Fri Mar 13 14:35:14 2009 -0700
+++ b/linux/drivers/media/dvb/dvb-usb/cxusb.c	Tue Mar 17 23:20:00 2009 +0800
@@ -322,58 +322,11 @@
 	return 0;
 }
 
-static void cxusb_d680_dmb_drain_message(struct dvb_usb_device *d)
-{
-	int       ep = d->props.generic_bulk_ctrl_endpoint;
-	const int timeout = 100;
-	const int junk_len = 32;
-	u8        *junk;
-	int       rd_count;
-
-	/* Discard remaining data in video pipe */
-	junk = kmalloc(junk_len, GFP_KERNEL);
-	if (!junk)
-		return;
-	while (1) {
-		if (usb_bulk_msg(d->udev,
-			usb_rcvbulkpipe(d->udev, ep),
-			junk, junk_len, &rd_count, timeout) < 0)
-			break;
-		if (!rd_count)
-			break;
-	}
-	kfree(junk);
-}
-
-static void cxusb_d680_dmb_drain_video(struct dvb_usb_device *d)
-{
-	struct usb_data_stream_properties *p = &d->props.adapter[0].stream;
-	const int timeout = 100;
-	const int junk_len = p->u.bulk.buffersize;
-	u8        *junk;
-	int       rd_count;
-
-	/* Discard remaining data in video pipe */
-	junk = kmalloc(junk_len, GFP_KERNEL);
-	if (!junk)
-		return;
-	while (1) {
-		if (usb_bulk_msg(d->udev,
-			usb_rcvbulkpipe(d->udev, p->endpoint),
-			junk, junk_len, &rd_count, timeout) < 0)
-			break;
-		if (!rd_count)
-			break;
-	}
-	kfree(junk);
-}
-
 static int cxusb_d680_dmb_streaming_ctrl(
 		struct dvb_usb_adapter *adap, int onoff)
 {
 	if (onoff) {
 		u8 buf[2] = { 0x03, 0x00 };
-		cxusb_d680_dmb_drain_video(adap->dev);
 		return cxusb_ctrl_msg(adap->dev, CMD_STREAMING_ON,
 			buf, sizeof(buf), NULL, 0);
 	} else {
@@ -1118,13 +1081,6 @@
 	usb_clear_halt(d->udev,
 		usb_rcvbulkpipe(d->udev, d->props.adapter[0].stream.endpoint));
 
-	/* Drain USB pipes to avoid hang after reboot */
-	for (n = 0;  n < 5;  n++) {
-		cxusb_d680_dmb_drain_message(d);
-		cxusb_d680_dmb_drain_video(d);
-		msleep(200);
-	}
-
 	/* Reset the tuner */
 	if (cxusb_d680_dmb_gpio_tuner(d, 0x07, 0) < 0) {
 		err("clear tuner gpio failed");