Friday, December 24, 2010

AMD ganged and unganged memory access

Last year I did a substantial upgrade on my desktop hardware.
Around that time I started noticing an issue with Ubuntu 9.10.
Maybe once a week or every other week the system would lock
up. Whatever was on the monitor would be frozen, keyboard
and mouse unresponsive, computer off the network, only
rebooting would fix it. If I was doing intensive DVD ripping
with dvd::rip it would happen a lot more often, like once a day.
I never observed this in Windows but I rarely have Windows
up for more than a few hours to play games. Upgrading to
Ubuntu 10.04 didn't fix the problem.

Since I've got some time and I'm doing intensive DVD ripping,
I thought I try to troubleshoot this.

(1) The BIOS (GA-MA790FXT-UD5P motherboard) has a 'load
fail-safe defaults' option to load conservative settings, tried that,
system still locks up.

(2) I looked at updating the BIOS. There's one version more
recent than what I've got on this one year old MB. It's a beta
and when I try to install it the flash application says it's got
a checksum error. Scratch that...

(3) Just cruising around in the BIOS menu I found a setting
for memory control mode: ganged or unganged.
Here's some discussion of what this means. Just kind of on
a whim I went ahead and changed this setting to ganged.

So after about 3 days of heavy DVD ripping the computer has
not locked up. Crossing my fingers. I won't really feel sure the
problem is fixed for a couple of weeks since it's so intermittent.

Friday, December 17, 2010

Ubuntu 10.04

It's the holiday season and that means OS upgrades.
I put the Ubuntu 10.10 CD in my home desktop and
tried to boot. It didn't even come up. I wonder if this
is the problem ESR mentioned. I put 10.10 on my two
grandchildren's laptops and didn't have any trouble.

I retreat back to 10.04. OK, boots fine. I'm a little
disappointed it doesn't detect my RAID but I know
how to do that manually.

It detects that I need a proprietary graphics driver
and downloads that... it figures out my USB wireless
device... a simple

mdadm -A /dev/md0

brings the RAID back up.

Wireless networking is unusably slow... there are
brief spikes of activity separated by long stretches with
no traffic flowing. I spent a couple of hours on this googling
and searching the forums. This magical incantation (I
wound up putting it in /etc/rc.local) fixed the problem:

sudo iwconfig wlan0 power off

See this thread.

Problem with hibernate using the 'Shut Down' applet
from the Gnome panel. Hibernation appears to work,
but resume from hibernate doesn't... system comes up
as from a cold reboot, but with networking disabled.
Problem is discussed at great length in bug 499940
and bug 577916, the latter of which appears to be still
open. None of the fixes described other than the
following workaround worked for me.

Workaround: I tried installing the 'hibernate' package
and running /usr/sbin/hibernate from the command line
(as root)... that seems to be working.

Slight bug in evince, see bug 572434. Fixed with

touch $HOME/.gnome2/evince/last_settings

I didn't need to do anything special to get Java and Flash
plugins installed into Mozilla, even running 64 bit. Nice.

It took me about a week to notice this but it seems the
distribution no longer includes the Lightning (calendar)
plugin for Mozilla Thunderbird. Just installing the
plugin from Tools->Add-ons didn't work. There was
some kind of incompatibility with 64-bit Thunderbird.
I was able to get it working by following this thread.

Update: my hibernate 'workaround' isn't really working.
This is keeping me from upgrading on my work box
where I use hibernate constantly switching back and
forth from Linux to Windows and I need this to be
fast and reliable. The last couple of times I tried
hibernate, when I went to resume I just wound up back
at the login screen.