V4L: pvrusb2: Fix video corruption on stream start

This introduces some extra cx23416 commands when streaming is
started.  The addition of these commands fix random sporadic video
corruption that can take place when the video stream is temporarily
disrupted through loss of signal (e.g. changing the channel in the RF
tuner).

This fix is already in the upstream driver source and has proven
itself there; this is a backport for the 2.6.20.y kernel series.

(backported from commit 6fe7d2c4)
Signed-off-by: Mike Isely <isely@pobox.com>
Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/media/video/pvrusb2/pvrusb2-encoder.c

@@ -288,6 +288,44 @@ static int pvr2_encoder_vcmd(struct pvr2_hdw *hdw, int cmd,
 	return pvr2_encoder_cmd(hdw,cmd,args,0,data);
 }
 
+
+/* This implements some extra setup for the encoder that seems to be
+   specific to the PVR USB2 hardware. */
+int pvr2_encoder_prep_config(struct pvr2_hdw *hdw)
+{
+	int ret = 0;
+	int encMisc3Arg = 0;
+
+	/* Mike Isely <isely@pobox.com> 22-Feb-2007 The windows driver
+	   sends the following list of ENC_MISC commands (for both
+	   24xxx and 29xxx devices).  Meanings are not entirely clear,
+	   however without the ENC_MISC(3,encMisc3Arg) command then we risk
+	   random perpetual video corruption whenever the video input
+	   breaks up for a moment (like when switching channels). */
+
+
+	/* This ENC_MISC(3,encMisc3Arg) command is critical - without
+	   it there will eventually be video corruption.  Also, the
+	   29xxx case is strange - the Windows driver is passing 1
+	   regardless of device type but if we have 1 for 29xxx device
+	   the video turns sluggish.  */
+	switch (hdw->hdw_type) {
+	case PVR2_HDW_TYPE_24XXX: encMisc3Arg = 1; break;
+	case PVR2_HDW_TYPE_29XXX: encMisc3Arg = 0; break;
+	default: break;
+	}
+	ret |= pvr2_encoder_vcmd(hdw, CX2341X_ENC_MISC,4, 3,
+				 encMisc3Arg,0,0);
+
+	ret |= pvr2_encoder_vcmd(hdw, CX2341X_ENC_MISC,4, 8,0,0,0);
+
+	ret |= pvr2_encoder_vcmd(hdw, CX2341X_ENC_MISC,4, 0,3,0,0);
+	ret |= pvr2_encoder_vcmd(hdw, CX2341X_ENC_MISC,4,15,0,0,0);
+
+	return ret;
+}
+
+
 int pvr2_encoder_configure(struct pvr2_hdw *hdw)
 {
 	int ret;
@@ -302,6 +340,8 @@ int pvr2_encoder_configure(struct pvr2_hdw *hdw)
 
 	ret = 0;
 
+	ret |= pvr2_encoder_prep_config(hdw);
+
 	if (!ret) ret = pvr2_encoder_vcmd(
 		hdw,CX2341X_ENC_SET_NUM_VSYNC_LINES, 2,
 		0xf0, 0xf0);