Integrating OS power management with the X server

[Eric Anholt]

On Mon, 2004-10-25 at 10:59, Nate Lawson wrote:
> I am the FreeBSD ACPI maintainer and recently someone brought to my 
> attention that the X server expects notification/control over the 
> suspend/resume process. This event is implemented in this file:
> 
> xc/programs/Xserver/hw/xfree86/os-support/bsd/bsd_apm.c
> 
> This interface works for apm (except that it only has NetBSD defines 
> currently) but is not implemented for ACPI.  I'd like more information
> as to what the X server actually does with this event.  Is there any
> situation where it actually needs to veto a suspend?  Does it
> potentially take seconds to save state?  Does it need to access other
> running subsystems or is it self-contained?

With DRI drivers that don't have any explicit support for suspend/resume
(radeon is the only one so far), I expect things will explode nicely if
they don't get to veto.  The DRM could do the veto easily, but I'm not
sure how to make sure the veto doesn't happen when you're switched to a
VT, which should be safe.

(Oh, and "potentially take seconds" -- definitely)

-- 
Eric Anholt                                eta at lclark.edu          
http://people.freebsd.org/~anholt/         anholt at FreeBSD.org