Most recent kernel where this bug did not occur: New laptop, only ever seen 2.6.21 and 2.6.22 Distribution: Fedora 7 Hardware Environment: Thinkpad T60p Widescreen Software Environment: Fedora 7 init scripts Problem Description: Laptop hangs in rc.sysinit when trying to load ACPI module video.ko. Seems to be related to nmi_watchdog=1 and to a warm reboot, but sometimes works even then. Steps to reproduce: Add nmi_watchdog=1 to kernel command line via grub, then reboot. Laptop will *probably* hang when it tries to load video.ko during boot-up.
Created attachment 12042 [details] DMIDECODE output
Created attachment 12043 [details] lspci ouput
Created attachment 12044 [details] dmesg log
Created attachment 12045 [details] /proc/interrupts output
Created attachment 12046 [details] configuration
Also seems to hang when trying to read ACPI video-related files in /proc, when nmi_watchdog=1. (I haven't tried yet when nmi_watchdog=0 - a job for tonight, probably.)
Someone has told me via email: "NEVER use nmi_watchdog on thinkpads. IBM/Lenovo's crap of a SMBIOS is deeply alergic to NMIs while handling a SMI. I don't know why the nmi_watchdog is not blacklisted on thinkpads, I recall someone wanted to do that and sent a patch..." So it looks like this is a SMBIOS bug. Ugh.
have you confirmed that the issue goes away with nmi_watchdog=0? does it make any difference if the ibm_acpi/thinkpad_acpi driver is loaded or not -- or does this depend just on the ACPI video driver?
The laptop is stable with nmi_watchdog=0. (Fortunately so, or it would be completely useless.) Once, when I tried loading the fglrx module, the kernel complained about a spurious NMI, tried blaming the hardware and said that it was going to try soldiering on anyway. I am therefore thinking that maybe I should be enabling NMIs. (No, none of the information here was gathered with the fglrx module ever have being loaded.) I have not noticed any issue with the thinkpad_acpi driver. The Fedora 7 rc.sysinit script loads every ACPI module in the /lib/modules/x.x.x.x/kernel/drivers/acpi directory, forcing me to load thinkpad_acpi myself later in rc.local, so thinkpad_acpi is usually not loaded when video.ko hangs. Having said that, I have known the laptop to hang when I was reading some of the files in /proc/acpi/video while nmi_watchdog=1.
seems we have a resolution here. resolve this bug.