Comment 21 for bug 16961

Relating to bug reports #17763 and #16961 on Ubuntu

I too had these random Freezes on my system. It worked fine on old configuration, but when I changed cpu and memory, cpu frequensy scaling didn't work any more. And it hanged system randomly so I had to reset. Those errors were printed on terminal and keyboard stopped functioning. Little later everything freezed.

My working system was:
Ubuntu Edgy
Motherboard: Abit KN9 Ultra
CPU (old): AMD 64 AM2 3500+
Memory (old):2x 512MB Kingston 667Mhz DDR2 ECC
Video C: Asus 7600GS Top-silent
PSU: Korsair vx450w

New components added which created freezes:
CPU: AMD 64 AM2 x2 4600+
Memory: 2x 1GB Kingston 667Mhz DDR2 ECC

I ran memtest overnight without hit. BIOS flashing didn't change a thing and system was stable on any single cpu frequensy. I wrote this shell script to test cpu frequensy scaling: http://www.antti.miranto.fi/cpu.freq.test/cpu.frequensy.tester.sh This generated error messages or freezed my computer on minutes instead of hours. More on that script at the end.

Next I changed new prosessor to other motherboard and run same script and same Ubuntu release (Feisty live-cd) for few hours without single hit. I got same results with using Gutsy's latest available kernel on Edgy system.

I send motherboard to waranty repair so currently I can't do any tests. I should have tested this on other linux distro too...

I put my error-logs and other stuff to web: http://www.antti.miranto.fi/cpu.freq.test/ (file: "ohjeet..." is a finnish guide to script which I wrote for the company where I bought this motherboard.)

Back to the script. Script runs gzip and bzip2 on every core and checks md5sums for compressed output. Md5sums should be same all the time! At the same time it changes cpu frequensy about every 0.1 second. This script doesn't use powernowd but cpufreq-selector command from gnome-applets package.

If you want to run it ($ sings means commands) follow forward.
***DO NOT USE THIS IN PRODUCTION ENVIRONMENT***
Broken hardware can do anyting except erase your data. :)

boot to Ubuntu live cd.

Script requires taskset program on schedutils package and tries to install it. Apt method doesn't work directy on live-cd for repository reasons so get the package and plase it to /tmp with root as a owner.

get the script and deb-file:
$ wget -nH -r --no-parent -A.sh -A.deb -A.txt http://www.antti.miranto.fi/cpu.freq.test/

change dir:
$ cd cpu.freq.test/

Change permissions and copy schedutils-package to beter place (last may ask your passwd):
$ chmod 775 cpu.frequensy.tester.sh
$ cp schedutils_1.5.0-1_i386.deb /tmp/
$ sudo chown root: /tmp/schedutils_1.5.0-1_i386.deb

Run the test (this may ask your passwd):
$ sudo ./cpu.frequensy.tester.sh

Results:
This script should run days without hit! If your computer locks up, some
program freezes partially or totally or you get md5sum missmatch there
might be hardware problem on your system or Ubuntu has a trouble to
handle your hardware.

Questions and comments: <email address hidden>