macdrv: implement getting and setting the screen saver state, version 2

[Ken Thomases]

On Jan 21, 2013, at 9:31 AM, C.W. Betts wrote:

> On Jan 20, 2013, at 11:06 PM, Ken Thomases <ken at codeweavers.com> wrote:
> 
>> I'm not sure it's correct that these are two different names for roughly the same thing.  I think the two assertion types do slightly different things.  "NoDisplaySleep" seeks to prevent display sleep for any (non-forced) reason.  "PreventUserIdleDisplaySleep" only seeks to prevent display sleep that is due to user idleness.
> From the header for kIOPMAssertionTypeNoDisplaySleep: Deprecated in 10.7; Please use assertion type kIOPMAssertionTypePreventUserIdleDisplaySleep. From Apple Docs, kIOPMAssertionTypePreventUserIdleDisplaySleep is only available on 10.7 or later.

I can't be certain, because Apple hasn't documented this API very well, but I believe that NoDisplaySleep is deprecated because Apple doesn't like its semantics.  It's not because it's just an old name for PreventUserIdleDisplaySleep; it's because PreventUserIdleDisplaySleep has better semantics.

> I don't think kIOPMAssertionTypePreventUserIdleDisplaySleep will do anything on 10.6

Right.

I wasn't suggesting that you use PreventUserIdleDisplaySleep on 10.6.  The code itself is fine.  I'm just saying that your comments were misleading because they suggest there are two different names for the same thing.

-Ken