Questions on How Xorg handle ACPI

Matthew Garrett mjg59 at
Wed Feb 18 05:45:08 PST 2009

On Wed, Feb 18, 2009 at 10:41:31AM +0800, sheldon wrote:

>    I'm trying to find how Xorg handles ACPI (s3 and s4).  It seems that Xorg
>    handles S3/S4( suspend and resume) is just the same as it process VT
>    switching, for both the flow is WaitFofSomething( )-> WakeUpHandle( ) ->
>    xf86Wakeup( ) -> xf86VTswitch( ) .

Xorg doesn't handle S3/S4.

>    Question 1. Is any different between Xorg handle S3/S4 and VT Switching?

No - suspend/resume will typically be implemented by VT switching (see 
pm-utils or the kernel's own VT switching in kernel/power/main.c)

>    BUT, xf86HandlePMEvents( ) is never called (I'm using Ubuntu8.10, Xorg
>    1.5.2 *C- a debug version ,compiled by myself). In my system S3/S4 is OK
>    in both console and X.
>    Question 2. I don't know why, Is Xorg don't need to read ACPI Events ? or
>    using some other methods

There are no ACPI events that Xorg can usefully respond to directly. 
They're all passed to userspace which will take appropriate actions.

Matthew Garrett | mjg59 at

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