[linux-dvb] Re: Another issue: frontend timeout value and low symbol rates

[Johannes Stezenbach <js@convergence.de>]

Andrew de Quincey wrote:
> 
> Hi, I've finally found the problem (after much fiddling)
> 
> The linux core drivers already do the seeking-about mechanism you suggest if 
> it can't lock on to the supplied base frequency. And that works fine (seeks 
> about in steps of symbolrate/16000).
> 
> The problem is that with the frontend driver as it is/was, it retunes the 
> TSA5959 PLL every time. Retuning the PLL every few milliseconds doesn't seem 
> to agree with this module. 
> 
> Also, the PLL resolution is quite low (500kHz). I initially tried increasing 
> the resolution of the PLL but that didn't seem to help. If anything, it 
> seemed to worsen matters.
> 
> Instead, if the frequency change is quite small (i.e. its obviously seeking 
> about), I program the derotator frequency registers with the offset. I can 
> now reliably lock on to any frequency/symbolrate within a reasonable time 
> (i.e. sub-second).

If you're confident that this is a general improvement (i.e. you didn't
break anything when fixing tuning on low-SR TPs), please commit.
Or post patches for others to try, please.

Johannes


-- 
Info:
To unsubscribe send a mail to ecartis@linuxtv.org with "unsubscribe linux-dvb" as subject.