[Intel-gfx] [PATCH] i915: Fix opregion notifications

[Matthew Garrett]

On Tue, Jul 12, 2011 at 03:20:23PM -0700, Keith Packard wrote:

> Seriously? It's some kind of magic non-switch switch event? And you can
> tell by checking magic bits within the event?

The Intel drivers on Windows appear to have used 0x80 as a generic 
"Something's chanegd" notification, overloading it for docking, lid 
state change and display switch press. As a result of that right now 
we're sending a display switch event whenever one of these occurs. Less 
than ideal. Opregion gives us a magic field in shared OS/firmware memory 
that can be used to distinguish between these events.

> How can I test this and know if it works?

Tested on a Thinkpad X200. Make sure suspend is disabled, then close the 
lid. Open it again. The ACPI video input device will send a display 
switch event. Add this patch and repeat and the event will vanish. The 
display switch itself will still generate an event.

I'll send v2 now.

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