On Sun, 10 Feb 2002, Elias Rajczyk wrote: > > Someone a clue why some systems get stuck after the "reboot" command. > Linux just outs "Restarting system" and freezes. Is is as if Linuxbios > doesn't give it a second rundown
Linux doesn't quite handle reset right. We've found experimentally that most of the ways that Linux "reboots" involve the dreaded triple-fault. There's a lot of code to do restart in the kernel -- first try is the keyboard controller, second try is the 'go to 16-bit mode and call BIOS', third try is 'kick ourselves until we fall over (triple fault)'. We've found via tracing with the hardware In-Circuit Emulator that the 'go to 16-bit-mode' code is totally broken, the keyboard code is marginal, and that what happens most of the time is the triple-fault path. If you have a PIIX4E I have reset code that works. This is actually the Pentium's fault -- it has no RESET instruction, unlike earlier micros. ron
