[linux-dvb] Re: Budget DVB-C tuning problems; dirty solution

[Torbjörn Jansson <torbjorn.jansson@mbox200.swipnet.se>]

When I used czap to tune to ESPN I was surprised that I got a good picture
and a very low ber, on this computer I usualy get a very bad picture and
high ber.

So I left czap running for a few minutes and after a while the ber jumped up
and the picture went realy bad just as it usualy is.
Czap said that the signal was locked all the time.

Is it posibel that it somehow locks on to the wrong signal or something?

The only difference this time is that I had removed the dvb card for a while
before I tried.

> -----Original Message-----
> From: linux-dvb-bounce@linuxtv.org 
> [mailto:linux-dvb-bounce@linuxtv.org] On Behalf Of Antti Kaihola
> Sent: Saturday, February 07, 2004 2:46 PM
> To: linux-dvb@linuxtv.org
> Subject: [linux-dvb] Re: Budget DVB-C tuning problems; dirty solution
> 
> on 2004-02-07 at 12:57, I wrote:
> > > The rule seems to be:
> > > If I wait for more than 8 seconds after a successful tuning, the
> > tuning will fail.
> > > An immediate re-tuning attempt after a failed or successful tuning
> > will succeed.
> 
> 
> OK, here's a dirty modification which makes the no-lock 
> problem go away.
> This is from someone who doesn't understand shit about the driver and
> has never seen any hardware specifications, but was just poking around
> in the dark... :)  I just hope it helps others figure out 
> what the real
> problem is.
> 
> 
> In dvb_frontend.c function dvb_frontend_set_parameters(), add an extra
> call and a delay before the dvb_frontend_internal_ioctl call:
> 
> dvb_frontend_internal_ioctl (frontend, FE_SET_FRONTEND, 
> param); /* wake
> up! */
> dvb_delay(100); /* clear your head before action */
> err = dvb_frontend_internal_ioctl (frontend, FE_SET_FRONTEND, param);
> 
> 
> Somehow the extra ioctl call wakes the card up and properly 
> prepares it
> for the real action. I'm kind of simulating the
> two-tunings-in-a-row-succeed phenomenon I've encountered before.
> 
> With this ugly fix dvbtune now works correctly, i.e. tunes 
> successfully
> also after a longer pause than 8 seconds.
> 
> I haven't experimented too much with the delay in between, I just
> noticed that if I remove it, I still get some no-locks.
> 
> 



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