I’m running Fedora 15 on my main machine (old but reliable asus m2n sli deluxe mobo, 4 gig ram, athlon x2 5200+) very happily. So far it seems remarkably stable, reliable, and a pleasure to use. I do however have one odd issue though. Whenever I try to shut down, it (nearly ) always reboots a first time, then shuts down on a second attempt. Hardly a major issue, but one that’s had me scratching my head a bit. Does anyone have similar experience?
Maybe it’s connected to some hardware not behaving properly with ACPI… try disabling ACPI in the BIOS, and see if it shuts down cleanly… not as a solution, but as a test.
What happens when you run:
sudo halt -p
?
What happens when you hold Alt+SysReq and whilst holding them type REISUO (leave a couple of seconds between each letter) ? … some PC’s seem to require AltGr instead of Alt
Does:
sudo shutdown -P
result in shutdown or reboot ?
Sounds like a hardware problem with ACPI like Mark said. You should turn off the ACPI in the BIOS, and then shut-down again as a test.
Thank you both for your advice. I am working through the list of suggestions and will post as soon as I get something conclusive. Easier said than done though, because as I mentioned, the problem isn’t 100% guaranteed to reproduce. (And never happens the second consecutive time I shut down!) so far I can affirm that sudo halt -p makes no difference. I’m now playing with ACPI in thie bios. I can think of no better way to spend a Sunday afternoon…
… not all hardware works as it should, I have an “IBM PC” (literally) which refuses to power off on shutdown.
(1.4G Celeron model. built by Lenovo just after IBM sold their PC division)
Never really found a solution, but then looking at the other (pretty crappy) hardware on the box, it’s not entirely surprising that not everything works …
Upgrading to a current / generic motherboard would be almost guaranteed to solve your problem … 
Just to prove I listen, I took your advice. Just happened to be passing my favourite hardware emporium, and thought the time may have come for a new motherboard…
Anyway, I installed it, got everything nicely plugged in, turned it on, and… Bingo! no reboot problems. Still feeling all warm inside at not having to reinstall Fedora as well!
Did Fedora 15 complain at all ? … that’s something I’ve grown to love about Linux… swap a major component, and it just gets on with any reconfiguring without blue screening due to driver conflicts etc. … and no phone call to re-activate 
Had time to give it a thorough testing now. Not a single complaint from Fedora. Took a bit longer to boot up first time, but there have been no problems to speak of. I did have to fiddle with the alsamixer a bit, but it took a minute, and hardly counts as a problem. When I look at the struggles I’ve had in the past with a certain other system…
Thanks again for the help guys!