[linux-dvb] Re: [POLL] kdvb-fe, tune at initialisation, powermanagement

[Holger Waechtler <holger@convergence.de>]

Wolfgang Wershofen wrote:
> Dienstag, 29. Oktober 2002 at 10:13 Holger Waechtler wrote:
> 
> (...)
> 
> 
>>The bad thing is that you explicitly have to disable power management 
>>for networking over DVB (or run an application all the time which 
>>processes frontend events;)
> 
> 
> Does this mean, you'll have to tune the card new every time, the card is
> revived. Or the other way round: does tuning e.g. with dvbtune wake up
> the card?

calling dvbtune will open the frontend device and thus waking up the 
card. As soon dvbtune dies the filedescriptor will be closed and the 
frontend will get shutted down unless you explicitly disabled power 
management.


> I run my budget-card only for sat-networking purposes in a router. At
> the moment I tune the card right after booting to the desired freq, set
> up the network interface and I'm done with that. If I were to use power
> management in that router (which I do not at the moment), would I have
> to tune the card every time, a connection to the internet is requested
> to make shure, the card is awake and has the right frequency?

In your case you want to disable power management by passing the 
dvb_shutdown_timeout=0 parameter.


> What happens to the network-interface, when the card is powered down?
> Do I have to re-ifconfig this? This would add some additional seconds
> during connection, which is a disadvantage for dial-on-demand systems.

It won't get any data.


> So I think, one has to decide between dial-on-demand and power
> management, when you apply the suggested changes. That's no problem for
> me but may be for others. Wouldn't it be possible to introduce some kind
> of driver option, with which the user can enable or disable power
> management according to his/her needs?

it's there, the parameter is called dvb_shutdown_timeout. When you pass 
a value of zero the frontend will always keep it's power.

Holger



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