Re: VESA DPMS Driver

From: Don Lewis <truckman_at_FreeBSD.org>
Date: Sat, 22 May 2004 16:21:44 -0700 (PDT)
On 30 Apr, John Baldwin wrote:
> On Thursday 29 April 2004 01:20 am, Benjamin Close wrote:
>> Hi All,
>>     I like many have suffered the battery drain of the laptop screen
>> remaining on while the system is suspended. I've created a driver that
>> allows the screen to be shutdown by DPMS provided acpi supports video
>> mode changes. Beware, this is my first kernel driver so it's nothing
>> great. Hopefully it will help someone with enough knowledge build a
>> better driver.
>>
>> It's a loadable kernel module and the only tweak required to get it
>> compiling should be in the Makefile.
>>
>> You can grab it from:
>> http://www.clearchain.com/people/benjsc/download/vesa_dpms.tar.gz
>> A URL as the list strips attachments.
> 
> I merged this into the acpi_video(4) driver (which already takes over ACPI 
> devices with a DOD, etc. handle) so that the two drivers aren't mutually 
> exclusive.  Unfortunately, my laptop doesn't have any _DOD, etc. methods for 
> its video device so I can't test it.  It's somewhat hackish as only i386 has 
> VM86 support, but the patch is at:
> 
> http://www.FreeBSD.org/~jhb/patches/acpi_video_dpms.patch

It doesn't seem to do anything on my Thinkpad R40.  If I run
	xset +dpms; xset force dpms off; xset q
xset tells me that the monitor is in the off state, but there are no
visible changes to the backlight or display.  This was also true without
the patch.

The backlight shuts off in the S3 state, but happens even without
acpi_video loaded.  Also, the backlight intensity buttons do not appear
to require any OS support.  They have just always worked.

My laptop does have a _DOD method.
Received on Sat May 22 2004 - 14:21:59 UTC

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