[linux-dvb] HVR-4000 and analogue tv

Anders Semb Hermansen anders at ginandtonic.no
Wed Sep 24 20:39:23 CEST 2008

Den 24. sep.. 2008 kl. 19.20 skrev Darron Broad:


> <snip>
>> Does this mean that mythtv is doing something weird or maybe just
>> using the v4l api in a different way which the driver cannot handle?
> This is feasable. I will take a look if I get the time but this
> is more than likely to be when I have other reasons to look
> at mythtv so don't expect an immediate response :-)

I did some more investigating.

I thought maybe this had something to do with the tuner, since I got  
snow. So I enabled debugging for the tuner module (debug=1). What I  
saw was that when I started watching TV in myth, there was a  
TUNER_SET_STANDBY after frequency and other things was set. This  
TUNER_SET_STANDBY did not appear when I was just changing channel (and  
picture worked).

So I searched the driver for TUNER_STANDBY and found one which I  
tried. Here is what I did:

diff -r e5ca4534b543 linux/drivers/media/video/cx88/cx88-video.c
--- a/linux/drivers/media/video/cx88/cx88-video.c       Tue Sep 09  
08:29:56 2008 -0700
+++ b/linux/drivers/media/video/cx88/cx88-video.c       Wed Sep 24  
20:35:46 2008 +0200
@@ -1152,7 +1152,8 @@
         file->private_data = NULL;

-       cx88_call_i2c_clients (dev->core, TUNER_SET_STANDBY, NULL);
+       printk("Don't set standby mode! TUNER_SET_STANDBY NO SIR!");
+       //cx88_call_i2c_clients (dev->core, TUNER_SET_STANDBY, NULL);

         return 0;

This fixed it!!

I don't know what side effects this will have. Or if this is caused by  
wrong use of v4l by mythtv, or driver not implementing it correctly.  
Those who know the codebase can maybe answer that and come up with a  
better permanent solution.

Best regards,

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