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

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

----- Original Message -----
From: "Rene Bartsch" <ml@bartschnet.de>

> 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).

Ah, ok. Sorry, I didn't knew about power management in the DVB driver
before.



> Could you measure that with a current DVB-Head driver and
> power-management enabled?

Sorry again, but i need an up-to-date setup first. Currently, I still have
VDR 1.0.4, because i need to update the kernel in order to be able to use
one of the recent drivers. I plan to do this together with the integration
of a bigger HDD, but unfortunately there are some problems ordering one....
Sure, I'll do some measurements with the new setup, but i can't tell you
when this will happen.



> 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?

I've done this with a true-RMS power measurement-set. Not the best one, not
very accurate, but at least there shouldn't be any conceptual errors in the
measurment process. Simply calculating from measured voltage and current
will not work, because one have to take the current waveform and power
factor (phase shift) into account. (Well, I'm pretty sure you are aware of
this ;-)

The only problem with this measurement setup is the unknown and most likely
non-linear efficiency ratio of the PSU. But it should be sufficient to get a
rough idea of which power saving strategies really saves power ;-)

greetings,
Christian





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