[linux-dvb] [PATCH] AverMedia AverTV DVB-T 761

Johannes Stezenbach js at linuxtv.org
Sat Sep 10 18:57:02 CEST 2005


On Sat, Sep 03, 2005 Jyrki Niskala wrote:
> This patch gives better performance when using high frequencies (over 
> 470 MHz). I got those new
> charge pump values by i2c-snooping windows drivers.
...
> --- dvb-kernel/linux/drivers/media/dvb/bt8xx/org-dvb-bt8xx.c    
> 2005-09-03 19:21:55.000000000 +0200
> +++ dvb-kernel/linux/drivers/media/dvb/bt8xx/dvb-bt8xx.c        
> 2005-09-03 19:23:11.000000000 +0200
> @@ -264,10 +264,10 @@
>                cpump = 1;
>        else if (params->frequency < 470000000)
>                cpump = 2;
> -       else if (params->frequency < 750000000)
> -               cpump = 2;
> -       else
> -               cpump = 3;
> +        else if (params->frequency < 750000000)
> +               cpump = 0x40;
> +        else
> +               cpump = 0xc0;
> 
>        if (params->frequency < 175000000)
>                band_select = 0x0e;

Hm, that's not the real fix, there seems to be another bug.
Can you try the following patch:


--- linux/drivers/media/dvb/bt8xx/dvb-bt8xx.c	10 Sep 2005 07:26:02 -0000	1.49
+++ linux/drivers/media/dvb/bt8xx/dvb-bt8xx.c	10 Sep 2005 16:52:52 -0000
@@ -280,7 +280,7 @@ static int microtune_mt7202dtf_pll_set(s
 	data[0] = (div >> 8) & 0x7f;
 	data[1] = div & 0xff;
 	data[2] = ((div >> 10) & 0x60) | cfg;
-	data[3] = cpump | band_select;
+	data[3] = (cpump << 6) | band_select;
 
 	i2c_transfer(card->i2c_adapter, &msg, 1);
 	return (div * 166666 - 36000000);

Additionally the Windows driver seems to use slightly
different charge pump settings (1 vs. 2 in the 470...750MHz range),
can you test which one actually works better?

Thanks,
Johannes



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