Re: API to turn off the display

From: John Baldwin <jhb_at_FreeBSD.org>
Date: Fri, 30 Jan 2004 13:06:57 -0500
On Friday 30 January 2004 10:36 am, M. Warner Losh wrote:
> In message: <20040130092529.GA725_at_laptop.6bone.nl>
>
>             Mark Santcroos <marks_at_ripe.net> writes:
> : On Thu, Jan 29, 2004 at 11:32:54AM -0500, John Baldwin wrote:
> : > I read the spec yesterday, and what is supposed to happen is this:  The
> : > display (LCD, CRT, etc.) is supposed to be powered down using DPMS. 
> : > The actual adapter is then supposed to be powered down using either PCI
> : > or ACPI sleep states, and the adapter should not be powered down to a
> : > lower sleep state (like D3) w/o using DPMS to power the display down to
> : > at least that state first.  This means that the kernel might need to
> : > grow a dummy vga driver of some sort and some simple dpms support for
> : > suspend/resume.
> :
> : I second this.
> :
> : Nate, can you put it on your acpi-todo list?
>
> The only problem with having a vga device for suspend/resume is that
> it will claim devices that drm wants to claim later and X won't work.
>
> I have about the simplest driver possible for vga in one of my trees,
> and found this to be a problem on my dell i8k.

Yes, we need a way I think to have multiple drivers attach to a device, or 
maybe have the drm drivers attach as a child of the vga device instead.  For 
the intel motherboards with onboard graphics, we already have this problem 
where drm and agp both want the same device.  Having a model of:

vga0
  drm0
  agp0

Might be the sanest way to do this cleanly.

-- 
John Baldwin <jhb_at_FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve"  =  http://www.FreeBSD.org
Received on Fri Jan 30 2004 - 09:08:43 UTC

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