R51 power problems / linux

[david.guichard]

I'm running linux on an R51. Recently it started having power problems and the details are a bit odd.

If the laptop is unplugged from AC, it immediately shuts down and tries to reboot--not a nice system shutdown, but like pulling the power completely.

On battery only, it won't boot. It gets through grub fine, but as soon as it says that it's booting the kernel, it switches off, then tries to reboot again. Occasionally it gets somewhat farther before crashing. This crash-reboot appears to continue forever. Plugging in AC again allows it to boot.

Nothing in the logs that I can see.

On battery alone, it will boot fine from a live cd, like knoppix.

The battery is getting old, and doesn't provide as much time as it used to, so that was my first guess. I have an R52 with what appears to be an almost identical battery in very good shape. I tried that battery, and the behavior was the same.

Then I tried reinstalling the operating system--maybe that would avoid some bad blocks? No help.

Then I tried swapping the drive from the R52 into the R51. As I went to do that, I noticed that the retaining screw on the drive had gone missing. With the R52's drive in, it worked fine in a brief test. So I reinstalled the original HD (including a screw) and it worked fine. Problem solved, yes? Apparently the drive just needed to be reseated.

Well, no. A few days go by, and it starts doing the same thing again. I tried reseating the HD a few times, no help. smartd reports no problems with the drive.

So it still appears that it might be related to the HD, since it boots from CD, but it's also clearly some sort of power-sensitive problem. I don't really want to buy a new drive without knowing that's the problem--it could be some internal problem involving the HD circuitry and some power differences between battery and AC, yes?

The only thing I can think to try at this point is an extended test with the R52 HD. If that works fine for, say, a week, then I suppose a new drive would be a good bet.

Anyone have any ideas?

[david.guichard]

I put the R52 drive into the R51 again. This time it refuses to boot on battery. So the HD seems not to be the problem.

Am I stuck with no battery or an expensive trip to a repair shop?

[userlander]

what version or distro of linux?

no real answers, just wondering if it might have something to do with acpi or apm? maybe you could disable whichever one of those might be running and see if it gives the same behavior.

[david.guichard]

It's fedora 5 and hadn't been changed for a long time when this behavior started.

It's possible I now have a fix, though I don't really understand what's going on. In the bios, I changed the "CPU power management" setting from automatic to disabled, and the problem disappeared. When I set it back to automatic, it crashed trying to reboot; back to disabled and it's fine again. It will boot on battery and pulling the AC doesn't crash the machine.

Anybody know enough to explain why this matters when running on battery from HD, but not from CD?

[whizkid]

This sounds like a good candidate for the Linux ThinkPad Mailing list: http://mailman.linux-thinkpad.org/mailm ... x-thinkpad

There are some very knowledgeable folks on that list.

But you'd probably be asked to see if you can install a newer kernel/OS. Fedora 9 is out and works well (but not as well as 8 in my experience).

Sometimes logs are not useful because the shutdown happens before they can be written to. Capturing the output from a serial or network console could help.