Subject: Re: New power management framework for sysmon
To: Jason Thorpe <thorpej@wasabisystems.com>
From: Steven M. Bellovin <smb@research.att.com>
List: current-users
Date: 04/20/2003 14:04:15
In message <CCCC82B6-7352-11D7-BE58-000A957650EC@wasabisystems.com>, Jason Thor
pe writes:
>
>On Sunday, April 20, 2003, at 12:53  AM, Simon Burge wrote:
>
>> The last time I tryied ACPI on my laptop, the CPU fan stayed on all the
>> time.  It starts and stops when I have APM configured in my kernel.  
>> Has
>> this changed with ACPI yet?
>
>No, that would be the job of powerd, once the appropriate trigger 
>events are added, and fan control added.
>

I confess that that scares me.  If user level gets wedged -- to pick 
three plausible situations, if powerd depends on threads, which are
a bit buggy right now, or if powerd is waiting forever for some other 
script to complete (apmd seems to have that problem), or if the disk 
controller is hung, making it impossible to read the fan control script 
-- you could easily end up with a fried CPU.  Are there any safety 
mechanisms?


		--Steve Bellovin, http://www.research.att.com/~smb (me)
		http://www.wilyhacker.com (2nd edition of "Firewalls" book)