[vdr] Re: Shutdown frontend for saving power and heat

["Christian Vogt" <c.v@nexgo.de>]

----- Original Message -----
From: "Rene Bartsch" <ml@bartschnet.de>
>
> the DVB-driver automagically powers up and down the tuner-frontend when
> the device is accessed/released. So it would save a lot of current (e.g.
> weak PSU) and heat if VDR simply would release unused cards and all
> cards if the user-time-out has been reached.
>

Hi Rene,

we had a similar discussion in june 2002, but that time we thought about
completely unloading the driver to stop the ARM CPU on the full featured
cards to save power, reduce heat and (maybe) extend lifetime of the cards.
Here is what I've measured that time...

> It's a two DVB-s card System (one Rev.1.3, the other Rev.2.1) with only
> one wire to the LNB. I've measured the total power dissipation of the
> whole box (true-RMS at the AC-Line).
>
> - Machine up and running, DVB unloaded, VDR not running: 47,7W
> - only DVB driver loaded: 54W
> - additionally VDR started, watching TV using transfer mode: 57..59W
> - doing the timeshift-thing: 59..60W

So, from this values I'd assume to save not more than 1,5W per card just by
releasing the frontend.

Oh, by the way: Are you sure the driver powers down the tuner when the
device is idle? I don't think so, because the full featured cards start
receiving (and displaying) a channel as soon as the driver is loaded. IMHO,
If we want to reduce the power dissipation in idle mode, unloading the
driver is the way to go.

regards,
Christian




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