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

[Rene Bartsch <ml@bartschnet.de>]

Am Son, 2003-05-11 um 17.54 schrieb Christian Vogt:
> ----- Original Message -----
> From: "Rene Bartsch" <ml@bartschnet.de>
> >

> > 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.
> 

I didn't measure but tested power-management functions of DVB-driver
(2003-04-27 from VDR-ftp).

First, power-management is disabled by default as timeout ist set to "0"
in the make-script (for insmodding). I've set the value to "5" for
testing. When VDR was running all worked as exspected.

About five seconds after stopping VDR the picture froze to a nice
still-picture, which proofs the tuner-frontend has been powered down
(with power-management disabled the live-video was still running).

I don't know how the hardware allows power-down, but if the
DC/DC-converter is switched off powering off the complete frontend and
LNB this could save about 10 Watt per card (about 18 KW/month in my
case).

Could you measure that with a current DVB-Head driver and
power-management enabled? Please shutdown VDR completely while driver is
running to see how power-management decreases consumption.

Rene

P.S.: How did you measure consumption? With a measurement-set for AC
displaying Watts or did you calculate from measured AC-Voltage and
-current?



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