What is an ACPI GPE storm?

Question

Just experienced a system freeze (no touchpad, no keyboard, screen looked normal), Alt/SysRq/REISUB didn't work, had to press the start button.

In /var/log/kern.log I find:

ACPI: EC: GPE storm detected, transactions will use polling mode

Around the time of the freeze. The next entry is the first action of the next reboot.

Could this be related, and what could it mean?

I'm also experiencing frequent program crashes, always Segfaults and/or SIGSEVs mentioned in the crash report, the programs this is happening too seem random (mplayer, clementine, gnome subtitles, openshot, ...), but these never damage the system, I can always continue my work. All this makes me a bit worried about the stability of my system.

System details:

Ubuntu 12.04, 64-bit
3.2.0-25-generic Kernel
Intel® Core™ i5-2430M CPU @ 2.40GHz × 4 

Solution

ACPI is the Advanced Configuration and Power Interface, which allows Ubuntu (or any OS) to communicate with your hardware in a standard manner. It's main function is power management, along with hardware device configuration.

A GPE in ACPI is a General Purpose Event. Think of it as an interrupt - the hardware is informing the OS (via ACPI) that something happened. The "something" usually includes things like plugging/unplugging your AC adapter, closing/opening the lid of your laptop, etc.

EC is the embedded controller which provides ACPI functions on your motherboard.

A GPE storm occurs when the EC starts sending hundreds or thousands of "events" per second to the OS -- these are either spurious (bogus), or due to some fault in the underlying hardware. e.g. a failure in your battery's charging controller leads the ACPI EC to think that the battery is being removed and reinserted hundreds of times per second.

Transactions will use polling mode means that to handle the storm, the OS will stop using GPEs/interrupts to be informed of ACPI events and will instead -- on its own schedule -- "poll" or proactively ask the ACPI EC if any events it should know of have occurred. This way, the OS can still effectively perform ACPI functions while not being overwhelmed with a "GPE storm".

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As for your particular problem, yes, this error can certainly affect system stability and usually means something is wrong with your hardware and not Ubuntu/the kernel. If you experience frequent crashes, try running the Memory Test from the Ubuntu Live CD?

Comments

[Tinellus]

Thx, this helped. I wasn't plugging/unplugging or anything similar, but a couple of hours before I had to Alt/SysRq REISUB because the laptop wouldn't wake up after closing the lid and then (accidentally) unplugging. That could be related then.... And I'll certainly keep your suggestion of running the memory test in mind. Thanks