Re: [Mactel-linux-devel] ACPI on MacBook Pro

[Matthew G. <mj...@sr...>]

On Sun, Mar 26, 2006 at 01:10:14AM -0500, Jimmy Kaplowitz wrote:
> can see battery output. However, whether or not I have that module
> loaded, there is an annoying medium-high-pitched tone that continuously
> comes from my machine when it's in Linux and I have the power cable
> disconnected. It stops about a second after I plug in the power cable.
> What might be wrong here? It's very irritating.

Poor quality capacitors resonating when the CPU rapidly switches in and 
out of C2 and C3 powersaving states. Try poking different values into 
/sys/module/processor/parameters/max_cstate - you'll lose battery life, 
but the noise will stop. Alternatively, hacking your kernel to have a HZ 
value of 100 rather than 1000 should improve things.

> Also, how do I get any of the various ACPI sleep states to work?
> /sys/power/state says that standby (S1) and mem (S3) are supported, but
> when I echo "standby" or "mem" to that file I get Operation not
> permitted. Also, /proc/acpi/sleep doesn't exist. I am running acpid, but
> it doesn't work any better without that.

Sounds like you haven't built with CONFIG_ACPI_SLEEP. I wouldn't worry - 
having looked at the code, it's plainly impossible for suspend to work 
on EFI machines (code that's flagged __init is called in the suspend and 
resume paths, for instance). I'm working on fixing it up, we'll see if 
it actually gets anywhere.

-- 
Matthew Garrett | mj...@sr...