how to power off in 2.2.0-pre9/final

Marc Lehmann (pcg@goof.com)
Wed, 27 Jan 1999 19:59:53 +0100


I used to comment out the smp check in arch/i386/kernel/apm.c, since
power-off worked fine even with SMP.

In pre8, that check was removed and I could read the following log-entry:

* Add hack to allow power off of SMP systems by popular request.

sounds great, but now it doesn't power-off anymore. I decided to watch the
list before looking at the code, and indeed other people asked and were told:

use "apm=smp-power-off" on the commandline.

Looking at apm.c, I see:
if (apm_enabled || (smp_hack == 2))
(void) apm_set_power_state(APM_STATE_OFF);

I added a printk at that point which gave me values of apm_enabled=0 and
smp_hack=2 at this point, so power-off seems to be broken.

I then tried to remove the smp check altogether, which caused the kernel
to freeze at this point while booting.

Finally, I tried to move the smp check below the "if (apm_bios_info.version > 0x100)",
added an apm_enabled=1 before returning, and now it works fine again.

(I have an ASUS P2L97 board)

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