I recently bought an Enermax mini-ATX PSU for my dual boot Win/Lin desktop. One of the features is the fans stay on for a minute after shutdown to cool the system down properly. Long story short (and it pains me to have to say it this way but) it works in Windows and not Linux. When I shutdown Fedora Core 4 I can see a message that says something like "ACPI Shutdown", so I'm hoping threre's a kernel parameter or config file somewhere I could modify to alter this behavior. TIA for any clues/help.

I don't understand why you'd want that 'feature'. Once the system is powered off, there is no more heat entering the system. All that would happen if the fans stayed on is that the components cool off faster, which incidentally, would worse for them. Sudden changes in temperature will decrease the lifetime of anything.

Am I crazy?

It must be a feature for the new turbo charged PC so the turbo can cool down

heatsinks continue to disipate heat after the power goes off and case temps will actually rise if you stop ehausting the air immediately (though the much hotter CPU does start to cool immediately.) I've replaced several mobos recently with the tell-tale sign of a case temp prob, swollen capacitors. If the capacitors dry out your mobo is toast.

In any case, doesn't really matter if you understand (or agree) with the reason I want that "feature". It suffices that I do and that it doesn't work (in Linux.) Thanks for sharing your reason for not being interested in helping, though, I guess.

Swollen caps are a separate issue - usually crappy caps... The case temp isn't likely to rise too far for too long. I live in the tropics where it's 40C for long periods with several machines running, all running 100% CPU doing F@H - so I get a LOT of heat. No swollen caps or blown MB's yet, and I've been running PC's since there was such a thing

But more to the question, bever heard of this 'feature'. It's likely it's a window app that pauses the shutdown. Maybe something in the MB driver software. I don't know of any linux app like that, and I doubt there has been a lot of work on it... A lot of us linux users don't switch our PC's off so it's not something we think about

I didn't install anything in windows. Just plugged in the PSU and next shutdown fan stayed on. Anyway, I've been scratching my head trying to figure it out for a couple days now. FWIW, apparently it's a standard feature of Enermax PSUs and most people agree with you and don't like it. Unfortuantely that's about all my googling has turned up.

I don't know how well it would work, but you could put a script into runlevel 0 that just sits idle for 2 minutes or so. Save the script to /etc/init.d/rc0.d/S10delayshutdown

I don't dislike it. Don't really have an opinion of it really. My systems all stay up 24/7, so it's just not a feature I would use

It is interesting that it's just in the PSU tho. How does it know what OS is running...

Oh... How do you shut down? Do you use the front power button to shut down in windows and linux???

Just a standard shutdown via software. I think it's some APM/ACPI feature that's not being implemented in Linux though. Reason is when it's in that "mode" I have to press and hold front power button for three secs to force fan off early. So it would seem there's some kind of support in the BIOS for it. Anyway, if for no other reason than "I can do everyhting in Linux I can do in Windows" would be nice to figure it out.

From what I read, the fan shutdown is temperature controlled. Could it be that your computer is running hotter when running Windows?

The PSU fan speed is temp controlled too. I watch it go up and down when playing OpenGL games. To be clear, the "smart fan shutdown" feature is different; hard drive spins down, power light goes off on front panel, CPU is off... the PSU just stays on for about two minutes afterwards. I've never seen anything like it before. I have seen processor fans stay on that were plugged directly into the mobo, but here the PSU itself stays on after all the components are shutdown, I guess via ACPI signals, kind of like when suspending to memory...

Hi Crito, I'm using an Enermax PSU too and don't have the problem you talking about....
As far as I know, which isn't all that much, the fan control is not controled by the MB but by thermal sensors in the PSU and that regardless of opperating system the fans run for up to 2 minutes. The only thing I can think of could be the FAN MONITOR FUNCTION connector. Try without this plugged into the MB and let us know if that helped.

try using amd instead of intell

Thanks for reply kirry_boy, Gives me hope that there's indeed a way to alter this behavior. I've tried with the PSU fan speed sensor plugged in and unplugged from mobo with same result, works in Win but not Lin. Perhaps is something specific to my distro that's causing the problem... or perhpas there's something that gets set by Anaconda (RedHat's setup wizard) during initial install that's missing since I upgraded PSU after OS installation. In any case, this particular article expanded my ACPI understanding consdierably:
http://linuxgazette.net/106/pramode.html

Maybe things aren't getting as hot when you run Linux?