V4L/DVB (6828): cx88-blackbird: audio improvements

This patch should fix the 'muted audio' and 'raspy audio' problem for
mpeg2 streams out of cx88-blackbird devices.

Especially mythtv users would find that the audio would often sound bad
(aliased, or 'raspy'), mainly related to channel changes, many (all?)
other users would find that there was no audio at all in the mpeg data
from the encoder chip, unless the audio was manually unmuted.

The patch includes the following modifications:

Don't actually start the mpeg2 encoder until the device is read from
by the application.

Wait until the audio is stable for at least 400ms before starting the
mpeg encoder.

Mute/Unmute the audio when starting/stopping the mpeg encoder.

Stop the mpeg encoder when changing parameters and when changing tuner
frequency.

Add a variable 'mpeg_active' to struct cx8802_dev to allow tracking of
whether or not the mpeg2 encoder is active.

Load the firmware on cx88-blackbird driver load.

Signed-off-by: Jelle Foks <jelle@foks.8m.com>
Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

drivers/media/video/cx88/cx88-blackbird.c

@@ -536,6 +536,9 @@ static int blackbird_initialize_codec(struct cx8802_dev *dev)
 	dprintk(1,"Initialize codec\n");
 	retval = blackbird_api_cmd(dev, CX2341X_ENC_PING_FW, 0, 0); /* ping */
 	if (retval < 0) {
+
+		dev->mpeg_active = 0;
+
 		/* ping was not successful, reset and upload firmware */
 		cx_write(MO_SRST_IO, 0); /* SYS_RSTO=0 */
 		msleep(1);
@@ -572,38 +575,80 @@ static int blackbird_initialize_codec(struct cx8802_dev *dev)
 	blackbird_codec_settings(dev);
 	msleep(1);
 
-	/* blackbird_api_cmd(dev, IVTV_API_ASSIGN_NUM_VSYNC_LINES, 4, 0, 0xef, 0xef);
-	   blackbird_api_cmd(dev, IVTV_API_ASSIGN_NUM_VSYNC_LINES, 4, 0, 0xf0, 0xf0);
-	   blackbird_api_cmd(dev, IVTV_API_ASSIGN_NUM_VSYNC_LINES, 4, 0, 0x180, 0x180); */
 	blackbird_api_cmd(dev, CX2341X_ENC_SET_NUM_VSYNC_LINES, 2, 0,
 			BLACKBIRD_FIELD1_SAA7115,
 			BLACKBIRD_FIELD2_SAA7115
 		);
 
-	/* blackbird_api_cmd(dev, IVTV_API_ASSIGN_PLACEHOLDER, 12, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0); */
 	blackbird_api_cmd(dev, CX2341X_ENC_SET_PLACEHOLDER, 12, 0,
 			BLACKBIRD_CUSTOM_EXTENSION_USR_DATA,
 			0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0);
 
-	/* initialize the video input */
-	blackbird_api_cmd(dev, CX2341X_ENC_INITIALIZE_INPUT, 0, 0);
-
 	msleep(1);
+	return 0;
+}
+
+static int blackbird_start_codec(struct file *file, void *priv)
+{
+	struct cx8802_dev *dev  = ((struct cx8802_fh *)priv)->dev;
+	struct cx88_core *core = dev->core;
+	/* start capturing to the host interface */
+	u32 reg;
+
+	int i;
+	int lastchange = -1;
+	int lastval = 0;
+
+	for (i=0; (i < 10) && (i < (lastchange + 4)); i++)
+	{
+		reg = cx_read(AUD_STATUS);
+
+		dprintk(1,"AUD_STATUS:%dL: 0x%x\n", i, reg);
+		if ((reg & 0x0F) != lastval)
+		{
+			lastval = reg & 0x0F;
+			lastchange = i;
+		}
+		msleep(100);
+	}
+
+	/* unmute audio source */
+	cx_clear(AUD_VOL_CTL, (1 << 6));
 
 	blackbird_api_cmd(dev, CX2341X_ENC_MUTE_VIDEO, 1, 0, BLACKBIRD_UNMUTE);
 	msleep(1);
 	blackbird_api_cmd(dev, CX2341X_ENC_MUTE_AUDIO, 1, 0, BLACKBIRD_UNMUTE);
 	msleep(1);
 
+	blackbird_api_cmd(dev, CX2341X_ENC_REFRESH_INPUT, 0,0);
+
+	/* initialize the video input */
+	blackbird_api_cmd(dev, CX2341X_ENC_INITIALIZE_INPUT, 0, 0);
+
 	/* start capturing to the host interface */
-	/* blackbird_api_cmd(dev, CX2341X_ENC_START_CAPTURE, 2, 0, 0, 0x13); */
 	blackbird_api_cmd(dev, CX2341X_ENC_START_CAPTURE, 2, 0,
 			BLACKBIRD_MPEG_CAPTURE,
 			BLACKBIRD_RAW_BITS_NONE
 		);
 	msleep(10);
 
-	blackbird_api_cmd(dev, CX2341X_ENC_REFRESH_INPUT, 0,0);
+	dev->mpeg_active = 1;
+	return 0;
+}
+
+static int blackbird_stop_codec(struct cx8802_dev *dev)
+{
+	struct cx88_core *core = dev->core;
+
+	blackbird_api_cmd(dev, CX2341X_ENC_STOP_CAPTURE, 3, 0,
+			BLACKBIRD_END_NOW,
+			BLACKBIRD_MPEG_CAPTURE,
+			BLACKBIRD_RAW_BITS_NONE
+		);
+	/* mute audio source */
+	cx_set(AUD_VOL_CTL, (1 << 6));
+
+	dev->mpeg_active = 0;
 	return 0;
 }
 
@@ -833,6 +878,10 @@ static int vidioc_s_ext_ctrls (struct file *file, void *priv,
 
 	if (f->ctrl_class != V4L2_CTRL_CLASS_MPEG)
 		return -EINVAL;
+
+	if (dev->mpeg_active)
+		blackbird_stop_codec(dev);
+
 	p = dev->params;
 	err = cx2341x_ext_ctrls(&p, 0, f, VIDIOC_S_EXT_CTRLS);
 	if (!err) {
@@ -864,10 +913,9 @@ static int vidioc_s_frequency (struct file *file, void *priv,
 	struct cx8802_dev *dev  = fh->dev;
 	struct cx88_core  *core = dev->core;
 
-	blackbird_api_cmd(fh->dev, CX2341X_ENC_STOP_CAPTURE, 3, 0,
-				BLACKBIRD_END_NOW,
-				BLACKBIRD_MPEG_CAPTURE,
-				BLACKBIRD_RAW_BITS_NONE);
+	if (dev->mpeg_active)
+		blackbird_stop_codec(dev);
+
 	cx88_set_freq (core,f);
 	blackbird_initialize_codec(dev);
 	cx88_set_scale(dev->core, dev->width, dev->height,
@@ -1073,15 +1121,11 @@ static int mpeg_open(struct inode *inode, struct file *file)
 static int mpeg_release(struct inode *inode, struct file *file)
 {
 	struct cx8802_fh  *fh  = file->private_data;
-	struct cx8802_dev *dev = NULL;
+	struct cx8802_dev *dev = fh->dev;
 	struct cx8802_driver *drv = NULL;
 
-	/* blackbird_api_cmd(fh->dev, CX2341X_ENC_STOP_CAPTURE, 3, 0, BLACKBIRD_END_NOW, 0, 0x13); */
-	blackbird_api_cmd(fh->dev, CX2341X_ENC_STOP_CAPTURE, 3, 0,
-			BLACKBIRD_END_NOW,
-			BLACKBIRD_MPEG_CAPTURE,
-			BLACKBIRD_RAW_BITS_NONE
-		);
+	if (dev->mpeg_active)
+		blackbird_stop_codec(dev);
 
 	cx8802_cancel_buffers(fh->dev);
 	/* stop mpeg capture */
@@ -1107,6 +1151,10 @@ static ssize_t
 mpeg_read(struct file *file, char __user *data, size_t count, loff_t *ppos)
 {
 	struct cx8802_fh *fh = file->private_data;
+	struct cx8802_dev *dev = fh->dev;
+
+	if (!dev->mpeg_active)
+		blackbird_start_codec(file, fh);
 
 	return videobuf_read_stream(&fh->mpegq, data, count, ppos, 0,
 				    file->f_flags & O_NONBLOCK);
@@ -1282,6 +1330,7 @@ static int cx8802_blackbird_probe(struct cx8802_driver *drv)
 	       core->name);
 	host_setup(dev->core);
 
+	blackbird_initialize_codec(dev);
 	blackbird_register_video(dev);
 
 	/* initial device configuration: needed ? */

drivers/media/video/cx88/cx88.h

@@ -461,6 +461,7 @@ struct cx8802_dev {
 	u32                        mailbox;
 	int                        width;
 	int                        height;
+	unsigned char              mpeg_active; /* nonzero if mpeg encoder is active */
 
 	/* mpeg params */
 	struct cx2341x_mpeg_params params;