Ubuntu Precise i386 logged as gnome-classic Having some troubles with boot/reboot process, i've removed "quiet splash" from boot line to get the verbose mode. When i shutdown the system, i get the error above : latest 2 lines before it completly shutdown. After googling about this message, it seems related to usb devices plugged ; on this system they are two : a HP 4585 printer (power down) and a ps2 keyboard with usb adaptor. I cant see other warning/error while shuting down that system. But the bad effects are: - reboot never works - 1st cold boot ends with a kernel panic and the keyboard is lost - 2nd cold try to boot also fail: often dont get a post, or if i can get the boot line then it seems receiving a stop order - 3rd cold boot succeed this bug have been reported on Launchpad as bug #962113 https://bugs.launchpad.net/ubuntu/+source/linux/+bug/962113
Get this error also with the 3.3.0 kernel
The hub message isn't an error, and the acpi off message means we transferred control back to the BIOS. If it dies after that check for BIOS updates. To debug any more we really need to see the "kernel panic" you mention. If you get only a blank screen then there are ways and means with two boxes and a network cable to get any error logged to the other one.
This error is gone now with 3.4.01 kernel (generic-pae), only see this when shutting down: "mount / is busy" (one of the latest line before complete power off) but reboot is still an issue
Do the different reboot options help (see Documentation/kernel-parameters.txt) Try reboot=bios as a boot time option Others to try are reboot=cold reboot=warn reboot=pci reboot=triple If any of those help then we can set the default for a machine that way as an exception (assuming we can identify the machine)