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cab15625 05-05-2005 04:57 PM

ACPI suspend to ram ... no response
I'm using (and have tried everything from 2.6.8 onwards) on a toshiba satellite p10 with a P4 3.0 GHz hyperthreaded CPU. If I read the howto's properly, all I should have to do is issue the command

echo -n "mem" > /sys/power/state

as root and the laptop should go into a suspend-to-ram state. However, I get absolutely no response. Not even a complaint in the log files. Is there something obvious that I'm missing? Do I need to install some third party software?

Is there some way that I can at least get it to dump something to one of the log files or in some way acknowledge that I tried to do something it doesn't like so that I can start to fix the problem?

In desperation, I even tried adding "append acpi_sleep=s3_bios" to my lilo.conf file as well as going into runmode 1 and unmounting all possible modules before trying to suspend ... nothing.

It is very frustrating to go through these lists and see all sorts of people complaining that they have trouble when they reboot from a suspend ... at least it does something for them.

rpz 05-06-2005 01:41 PM

Get rid of mDNSResponder.

chkconfig mDNSResponder off

That stopped my computer from going to sleep. Don't know exactly what mDNSResponder is supposed to do (mDNS is something Apple uses for printer sharing, that's about as much as my knowledge go), but I haven't missed any feature (yet).

cab15625 05-06-2005 03:10 PM

Thanks for the heads up.

It turns out that's not the problem though. I found last night that if I recompile the kernel without SMP and SMT support (under processor options) then I get a response (it still doesn't come up cleanly, but at least I have somewhere to start now.) So I can start looking at other threads here to get me the rest of the way.

I've seen stuff on LKML where people talk about having suspend work with SMP on ppc systems. Does anyone know if there is any way to get it to work with SMP on an intel system? It would be nice to get suspend working on my laptop and still be able to use the capabilities of the hyperthreaded CPU.

rpz 05-06-2005 03:40 PM

Sorry if I misunderstand, but do you really want SMP on a laptop? As I recall, SMP is multiprocessor support, isn't it? Do you have a multiprocessor laptop or am I missing something here?

cab15625 05-06-2005 03:57 PM

Not really a multiprocessor laptop (though I have heard of such a beast). The hyperthreaded CPU (intel P4 HT) has some tricks it can do with the way it schedules operations so that it can act (almost) as if it was actually 2 cpus. If you really want to know how it works, there's a good writeup on ars at

The point is, if you have such a processor, and compile the kernel with SMP, you get a /proc/cpuinfo that reports two cpus and programs/libraries that can take advantage of it actually do see a speed improvement. I play around a lot with raytracing as a hobby and get impatient at times, so the "second" processor is nice (can render two frames at once with only about a 10-15% performance hit on each). But I also schlep the thing around alot, so the suspend functionality would be just as nice most of the time.

I believe there are other cpu's besides the intel p4 that can do this sort of thing. I'd be surprised if amd didn't have something just as nice, but I don't know for sure.

rpz 05-06-2005 06:47 PM

Oh I see. Nice indeed. Does it work with Pentium M:s too? (Wishful thinking :) )

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