> > > If the X server locks up, you can > > > always use alt+sysrq+u, alt+sysrq+b > > > > Magic sysrq's might only work at a console prompt. cf above, your keyboard > > may be inoperable. > > No, they always work, since it's all in the kernel, before it goes > through the "keyboard mode" stuff that kbdmode messes with. That > being the case, it doesn't matter if X is running and has your > keyboard in raw mode. You obviously don't see the output from your > keystrokes, but they show up in the kernel log messages, even > alt+sysrq+?. Hmm. Well, sysrq still needs to be turned on. (Here's where I can't tell you a good debian answer, since I usually build my own kernels)
> Err, one other thing that can bring down alt+sysrq: The system could > deadlock with interrupts disabled, in which case you lose, and nothing > will ever get through, not ethernet, not mouse, not keyboard, not > serial. I don't think X can disable interrupts, though, so as long as > the kernel isn't buggy, you're fine (he says optimistically... :) > > Anyway, we both agree that logging in remotely is the way to go. I > was just pointing out that, especially for this problem, you can get > away with not doing that if you can deal with the system when it's > having problems. (For the display-won't-sync problem, > nothing is going to happen that overwrites the kernel in memory or > whatever, so it's unlikely that the system will hang and require a > reboot.) Not unless you try to give X some exceedingly stupid options, anyway. My hubby once had to give X some directions about where video memory was really located. Mistyped. The hard disk controller he hit instead was *really* unhappy. Only had to fsck 6 times to clean everything up. But, these are laptops, you shouldn't be doing *THAT* :) If interrupts are deadlocked you'll probably lose the network too. It just depends. * Heather Stern * star@ many places...
