Freeze on mobo P5Q and C1E enabled

[Luigi Maselli]

My system is E8400, mainboard Asus P5Q.

If I leave C1E cpu feature enabled the system freezes every 2 minutes. C1E is enabled by default!

With C1E disabled Intrepid Ibex works well.

[Dean Loros (autocrosser)]

Same thing here with a Gigabyte GA-P35-DS3L motherboard. With it enabled--I was getting random freezes.

[Jay Modi (jaymode)]

I can confirm this bug also exists on an Abit AB9 Pro, which has the Intel P965 chipset. Disabling C1E in the BIOS solves the freezes.

[Leann Ogasawara (leannogasawara)]

The Ubuntu Kernel Team is planning to move to the 2.6.27 kernel for the upcoming Intrepid Ibex 8.10 release. As a result, the kernel team would appreciate it if you could please test this newer 2.6.27 Ubuntu kernel. There are one of two ways you should be able to test:

1) If you are comfortable installing packages on your own, the linux-image-2.6.27-* package is currently available for you to install and test.

--or--

2) The upcoming Alpha5 for Intrepid Ibex 8.10 will contain this newer 2.6.27 Ubuntu kernel. Alpha5 is set to be released Thursday Sept 4. Please watch http://www.ubuntu.com/testing for Alpha5 to be announced. You should then be able to test via a LiveCD.

Please let us know immediately if this newer 2.6.27 kernel resolves the bug reported here or if the issue remains. More importantly, please open a new bug report for each new bug/regression introduced by the 2.6.27 kernel and tag the bug report with 'linux-2.6.27'. Also, please specifically note if the issue does or does not appear in the 2.6.26 kernel. Thanks again, we really appreicate your help and feedback.

[DavidGN (davidgn)]

Abit IP35 Pro / E6750 / 8800GT

I am suffering occasional random freezes with 8.10 (updates to date). I tried disabling C1E and this seemed to fix the problem but after an hour or two the machine froze up again and required hard reset.

This problem has appeared in 8.10 for me. 8.04 did not suffer this problem on the same PC. I've read speculation that it may be the nVidia driver (177) at fault.

[Luigi Maselli (grigio)]

DavidONE: This bug is video card driver indipendent

[Moritz Naumann (mnaumann)]

That's possibly related to this discussion: http://lwn.net/Articles/286432/

[Luigi Maselli (grigio)]

Now C1E on P5Q can be enabled, the important is to set in the BIOS.

CPU RATIO: 9

[Leann Ogasawara (leannogasawara)]

Closing per the previous comment. Thanks.

[Clayton (cstanley)]

I saw this issue with an Asus p5q-deluxe motherboard, Intel E8400 Core 2 Duo processor, and Ubuntu 14.04.1 (Nov 1, 2014). The computer would freeze on average once per day (usb inputs would no longer work, screen frozen, no way to recover, etc.). After disabling C1E in the BIOS, the issue was resolved. I waited about 14 days to make sure that the change actually fixed the problem. It did.

During the process of troubleshooting, I switched out the video card (this motherboard does not have onboard video). The problem occurred both before and after the swap, so further evidence that the issue is an interaction with the p5q motherboard, 8400 CPU, C1E, and Ubuntu.

Not sure if this is worth looking into anymore since the motherboard is relatively old and is probably not still being used too much. But thankfully this thread from 2008-2009 was here. Otherwise I never would have found the workaround.