SMP kernel only brings up one CPU/core

[Trey Blancher]

This has worked with this particular kernel, and previous kernels, but lately my quad-core system has only been bringing up one CPU/core. I've attached debugging.txt, which contains the output of uname -a, cat /proc/cpuinfo, and dmesg. I figure there's about a 15% chance that all four cores will be brought up when I reboot, but I haven't been able to figure out how to force it to bring up all cores. Downgrading to previous kernels doesn't work. And booting into WinXP definitely shows all four cores, so I doubt it's a problem with the hardware (but I may be wrong about this).

ProblemType: Bug
Architecture: i386
DistroRelease: Ubuntu 8.10
NonfreeKernelModules: nvidia
Package: linux-image-2.6.27-11-generic 2.6.27-11.27
ProcCmdLine: root=UUID=5b026cc0-09be-4255-8023-54c95619ca42 ro cpus=4 splash
ProcEnviron:
 PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.27-11.27-generic
SourcePackage: linux

[Trey Blancher (ectospasm)]

I rebooted, and all four cores were brought up. I'm attaching the output of uname, cpuinfo, and dmesg again (not sure what ubuntu-bug is going to post here, so it may be superfluous).

[C. Cooke (ccooke)]

Hi, thanks for the bug report.

I'm marking this as a duplicate of #97554. Looks like the same problem.

I'm updating *that* bug to indicate it's still not fixed and applies to 2.6.27.

If you're able, would you mind checking to see if the bug is still applicable in Jaunty (9.04), currently at its fourth alpha release? There's a much higher chance of this bug being fixed in that release than any other.