cx25840: fix audio mute handling and reporting

From: Hans Verkuil <hverkuil@xs4all.nl>

Audio muting for the tuner input was implemented by stopping the audio
microcontroller and restarting it on unmute. However, it appears that this
method can actually crash the audio firmware. It's rare and seems to
happen with NTSC only.

It has been reimplemented by setting to volume to 0. In addition, the
reporting of the mute state has been improved as well: it used to be
impossible to detect whether the audio was muted by the user or if it
was muted due to the microcontroller trying to detect the audio
standard. This is now clearly stated.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>

1 files changed, 4 insertions, 2 deletions

diff --git a/linux/drivers/media/video/cx25840/cx25840-core.c b/linux/drivers/media/video/cx25840/cx25840-core.c
index 3392dacbd..08b986f05 100644
--- a/linux/drivers/media/video/cx25840/cx25840-core.c
+++ b/linux/drivers/media/video/cx25840/cx25840-core.c
@@ -936,6 +936,7 @@ static int cx25840_detect_client(struct i2c_adapter *adapter, int address,
 	state->audclk_freq = 48000;
 	state->pvr150_workaround = 0;
 	state->audmode = V4L2_TUNER_MODE_LANG1;
+	state->unmute_volume = -1;
 	state->vbi_line_offset = 8;
 	state->id = id;
 	state->rev = device_id;
@@ -1108,9 +1109,10 @@ static void log_audio_status(struct i2c_client *client)
 	}
 	v4l_info(client, "Detected audio standard:   %s\n", p);
 	v4l_info(client, "Audio muted:               %s\n",
-		    (mute_ctl & 0x2) ? "yes" : "no");
+		    (state->unmute_volume >= 0) ? "yes" : "no");
 	v4l_info(client, "Audio microcontroller:     %s\n",
-		    (download_ctl & 0x10) ? "running" : "stopped");
+		    (download_ctl & 0x10) ?
+				((mute_ctl & 0x2) ? "detecting" : "running") : "stopped");
 
 	switch (audio_config >> 4) {
 	case 0x00: p = "undefined"; break;