V4L/DVB: cx25840, v4l2-subdev, ivtv, pvrusb2: Fix ivtv/cx25840 tinny audio

This change attempts to fix the ivtv tinny audio problem by keeping digitizer
to encoder audio clocks running, while disabling the video clocks as needed to
avoid unpredictable PCI bus hangs.

To accomplish this, for the cx25840 module enabling of audio streaming had
to be separated from enabling video streaming, requiring an additional
v4l2_subdev_audio_op and calls to this new op in the pvrusb2 and ivtv drivers.

The cx231xx and cx23885 driver use the cx25840 module for affecting only
video on s_stream calls, so those drivers needed no change.

The CX23418 hardware does not exhibit either the tinny audio problem nor the PCI
bus hang, so the cx18 driver did not need corresponding changes.

CX2341[56] based cards that are not using the CX2584x family of chips
do not seem to be affected by the tinny audio problem, and this change should
not affect how they are configured. It will delay their first capture by
starting by another 300 msec though.

Many thanks go to Argus <pthorn-ivtvd@styx2002.no-ip.org> and
Martin Dauskardt <martin.dauskardt@gmx.de> whose persistent testing and
investigation of this problem will hopefully fix this problem once and for all
for many ivtv users.
Reported-by: NMartin Dauskardt <martin.dauskardt@gmx.de>
Reported-by: NArgus <pthorn-ivtvd@styx2002.no-ip.org>
Signed-off-by: NAndy Walls <awalls@radix.net>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/cx25840/cx25840-core.c

@@ -1347,30 +1347,59 @@ static int cx25840_s_register(struct v4l2_subdev *sd, struct v4l2_dbg_register *
 }
 #endif
 
+static int cx25840_s_audio_stream(struct v4l2_subdev *sd, int enable)
+{
+	struct cx25840_state *state = to_state(sd);
+	struct i2c_client *client = v4l2_get_subdevdata(sd);
+	u8 v;
+
+	if (is_cx2583x(state) || is_cx2388x(state) || is_cx231xx(state))
+		return 0;
+
+	v4l_dbg(1, cx25840_debug, client, "%s audio output\n",
+			enable ? "enable" : "disable");
+
+	if (enable) {
+		v = cx25840_read(client, 0x115) | 0x80;
+		cx25840_write(client, 0x115, v);
+		v = cx25840_read(client, 0x116) | 0x03;
+		cx25840_write(client, 0x116, v);
+	} else {
+		v = cx25840_read(client, 0x115) & ~(0x80);
+		cx25840_write(client, 0x115, v);
+		v = cx25840_read(client, 0x116) & ~(0x03);
+		cx25840_write(client, 0x116, v);
+	}
+	return 0;
+}
+
 static int cx25840_s_stream(struct v4l2_subdev *sd, int enable)
 {
 	struct cx25840_state *state = to_state(sd);
 	struct i2c_client *client = v4l2_get_subdevdata(sd);
+	u8 v;
 
-	v4l_dbg(1, cx25840_debug, client, "%s output\n",
+	v4l_dbg(1, cx25840_debug, client, "%s video output\n",
 			enable ? "enable" : "disable");
 	if (enable) {
 		if (is_cx2388x(state) || is_cx231xx(state)) {
-			u8 v = (cx25840_read(client, 0x421) | 0x0b);
+			v = cx25840_read(client, 0x421) | 0x0b;
 			cx25840_write(client, 0x421, v);
 		} else {
-			cx25840_write(client, 0x115,
-					is_cx2583x(state) ? 0x0c : 0x8c);
-			cx25840_write(client, 0x116,
-					is_cx2583x(state) ? 0x04 : 0x07);
+			v = cx25840_read(client, 0x115) | 0x0c;
+			cx25840_write(client, 0x115, v);
+			v = cx25840_read(client, 0x116) | 0x04;
+			cx25840_write(client, 0x116, v);
 		}
 	} else {
 		if (is_cx2388x(state) || is_cx231xx(state)) {
-			u8 v = cx25840_read(client, 0x421) & ~(0x0b);
+			v = cx25840_read(client, 0x421) & ~(0x0b);
 			cx25840_write(client, 0x421, v);
 		} else {
-			cx25840_write(client, 0x115, 0x00);
-			cx25840_write(client, 0x116, 0x00);
+			v = cx25840_read(client, 0x115) & ~(0x0c);
+			cx25840_write(client, 0x115, v);
+			v = cx25840_read(client, 0x116) & ~(0x04);
+			cx25840_write(client, 0x116, v);
 		}
 	}
 	return 0;
@@ -1601,6 +1630,7 @@ static const struct v4l2_subdev_tuner_ops cx25840_tuner_ops = {
 static const struct v4l2_subdev_audio_ops cx25840_audio_ops = {
 	.s_clock_freq = cx25840_s_clock_freq,
 	.s_routing = cx25840_s_audio_routing,
+	.s_stream = cx25840_s_audio_stream,
 };
 
 static const struct v4l2_subdev_video_ops cx25840_video_ops = {

drivers/media/video/ivtv/ivtv-streams.c

@@ -577,10 +577,14 @@ int ivtv_start_v4l2_encode_stream(struct ivtv_stream *s)
 		clear_bit(IVTV_F_I_EOS, &itv->i_flags);
 
 		/* Initialize Digitizer for Capture */
+		/* Avoid tinny audio problem - ensure audio clocks are going */
+		v4l2_subdev_call(itv->sd_audio, audio, s_stream, 1);
+		/* Avoid unpredictable PCI bus hang - disable video clocks */
 		v4l2_subdev_call(itv->sd_video, video, s_stream, 0);
 		ivtv_msleep_timeout(300, 1);
 		ivtv_vapi(itv, CX2341X_ENC_INITIALIZE_INPUT, 0);
 		v4l2_subdev_call(itv->sd_video, video, s_stream, 1);
+		ivtv_msleep_timeout(300, 1);
 	}
 
 	/* begin_capture */

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

@@ -1705,6 +1705,7 @@ static int pvr2_decoder_enable(struct pvr2_hdw *hdw,int enablefl)
 	pvr2_trace(PVR2_TRACE_CHIPS, "subdev v4l2 stream=%s",
 		   (enablefl ? "on" : "off"));
 	v4l2_device_call_all(&hdw->v4l2_dev, 0, video, s_stream, enablefl);
+	v4l2_device_call_all(&hdw->v4l2_dev, 0, audio, s_stream, enablefl);
 	if (hdw->decoder_client_id) {
 		/* We get here if the encoder has been noticed.  Otherwise
 		   we'll issue a warning to the user (which should

include/media/v4l2-subdev.h

@@ -180,6 +180,7 @@ struct v4l2_subdev_audio_ops {
 	int (*s_clock_freq)(struct v4l2_subdev *sd, u32 freq);
 	int (*s_i2s_clock_freq)(struct v4l2_subdev *sd, u32 freq);
 	int (*s_routing)(struct v4l2_subdev *sd, u32 input, u32 output, u32 config);
+	int (*s_stream)(struct v4l2_subdev *sd, int enable);
 };
 
 /*