Turning off the whole video susbsystem while keeping the cpu on

Guylhem Aznar olpc at guylhem.net
Mon Dec 1 00:42:46 EST 2008


I am wondering if there is currently any possbility to completely turn
off the whole video subsystem, while leaving the cpu running? [and is
it also possible to "reclaim" the video RAM for the system BTW ?]

That's for a screenless OLPC I'm experimenting with, and for which
there's no need to power the non-existent screen :-)

So I'm curious to try ; according to
http://wiki.laptop.org/go/Hardware_Power_Domains, I guess it should
also be possible to power down the DAC, video misc register and
graphic processor.

How can it be done? Is there an entry in /sys?

So far even dcon refuses to go into sleep :
echo 1 > /sys/devices/platform/dcon # sleep
$ cat /sys/devices/platform/dcon/sleep

The ec buttons are now working fine however.

Another question : what is the status of ec-wakeup, to replace
rtc-wakeup? (http://dev.laptop.org/ticket/4606)


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