[NTLUG:Discuss] Monitor shutdown

[Dan Carlson]

Monitor power management is performed according to the VESA DPMS (Display
Power Management Specification) spec.  Most VESA specs are not free, and
this one is no exception.

If you have a fully compliant VESA BIOS, you can perform monitor power
management with BIOS calls, which are specified in the VBE/PM (VESA BIOS
Extensions / Power Management) spec, also not free.

There is no additional data channel defined for DPMS (at least, the last
time I looked).  The information on which power state the monitor should be
in is passed from the host to the monitor using the video horizontal and
vertical sync signals:

On:  Both Horizontal and veritical sync pulses present.
Standby:  Horizontal pulses absent, Vertical pulses present.
Suspend:  Horizontal pulses present, Vertical pulses absent.
Off:  Both Horizontal and Vertical pulses absent.

If you have access to the display driver (X server, console frame buffer
driver, etc.) and you have technical documentation on the display
controller's CRT controller register set, then you have direct control over
the sync signals to put the monitor in the state you want it in.

Pulses for horizontal sync are defined as being present at greater than 10
KHz frequency.

Pulses for vertical sync are defined as being present at greater than 40 Hz
frequency.

So you don't have to drop the sync frequencies to zero, just below the
thresholds.  This is probably a concession to some CRT controllers that
can't be programmed down to zero.

Dan Carlson

----- Original Message -----
From: "Vaidya, Harshal (Cognizant)" <HarshalV at pun.COGNIZANT.COM>
To: <discuss at ntlug.org>
Sent: Sunday, August 04, 2002 11:27 PM
Subject: [NTLUG:Discuss] Monitor shutdown


> Hi,
>   Is there any way to shut down a computer monitor programmatically..
> locally or remotely?
>
> Regards,
> Harshal.
>
>