Re: [PATCH v4] ACPI: WMI: Add WMI-ACPI mapper driver

[Matthew Garrett <mjg59@srcf.ucam.org>]

On Tue, Oct 30, 2007 at 03:36:43AM +0000, Carlos Corbacho wrote:

> Event handling - allow a WMI based driver to register a notifier handler
> with WMI. When a notification is sent to WMI, WMI will execute _WED and
> then pass the results and the event to the external handler (since WMI
> does not know the meaning of an event, it is left to the external drivers
> to deal with, rather than WMI exporting the event to userspace).

I suspect that for a lot of cases, exporting this to userspace would be 
helpful - it's often easier for us to do this mapping in hal and just 
push out an updated fdi file than it would be to push out an updated 
kernel driver.

> Userspace - the WMI mapper disregards the WMI-ACPI spec on this point, and
> does _not_ try to export to userspace, since WMI does not exist on Linux.
> All callers of the WMI mapper are assumed to be kernel space drivers.

And for similar reasons, I think it would be helpful to provide 
userspace with the ability to trigger WMI calls. It's going to be easier 
for people to add GUIDs to a userspace file than to extend a kernel 
driver, even if there are some cases that are better handled by having a 
full in-kernel driver.

-- 
Matthew Garrett | mjg59@srcf.ucam.org