hi everybody,

My Ubuntu HTPC is shutting down by himself. By now I havent found out the reason for this behaviour. Please see the syslog grepped by "ACPI" below:

http://pastebin.com/gA0PhLur

Is it possibly a defective power button. Ive noticed the pnp device mentioned in the log starting from line 75.

It could be a BIOS issue, are there any BIOS upgrades available that might fix it ?

Hi, Welcome to Linux Questions!

You need to give us the syslog files showing time stamps to shutdown plus ones showing the following restart, not just a bit clipped out at random. (everything's logged at 22:41:19!!)We need to see what was happening over the shutdown and subsequent restart. If you wait a minute before restarting, it'll be easier to identify when it shut down. My system identifies a power button as a PNP ACPI device so I don't think that's relevant.

What sort of system is it; desktop, laptop? Some laptops will shut down with overtemp errors as the CPU heat exchanger fins become blocked with fluff and dust.

Play Bonny!

You may need to check your internal cooling system. I recently saw a desktop PC in a dumpster and was able to fish it out. The only surface problem was a bad hard drive. However, once I had Linux on it, it would shut down every five minutes. When I started poking around I discovered that the fan that cooled the CPU was stuck, which was causing the CPU to overheat....which, in turn, caused the PC to shut down. Once the CPU fan was unstuck the system worked great. So, check your fans etc. to make sure that everything is working the way that it should.

Hi 4ld3v

Common causes of unwanted shutdowns:
.CPU heat sink not making a clean interface to the CPU (eg. torn thermal pad, no heat sinking compound present, motherboard mounting bracket detached or broken, etc)
.CPU heatsink, or system enclosure choked with dust and debris
.CPU fan failed/disconnected
.Video display adapter cooling fan failed or failing (this is often overlooked, and results in random system restarts, lockups and failures)
.defective restart push button switch (rare)
.incorrectly seated adapters in AGP/PCI/ISA buses
.incorrectly seated adapter flyleads(cables)
.incorrectly seated memory modules
.faulty or incorrect specification memory modules (test using MemTest86)
.failing Power Supply unit (PSU)
.OS or application software corruption or incompatibilities
.Older PCs using old versions of ACPI and power management features
.Older PCs with BIOS incompatibilities

Hope that assists

Chris