Re: kernel 2.6.19: system freeze with blinking CapsLock and ScrollLock leds

[Gabor Gombas <gombasg@sztaki.hu>]

On Wed, Dec 06, 2006 at 04:01:28PM -0800, Max A. wrote:

> Why kernel in the case of panic cannot simply switch the screen to the
> text mode and print out a message there?

Because that is quite a complex task on a modern graphics card. Usually
there is no way to switch to a mode (be it text or graphics) without
knowing the current mode, and that information is only present in the X
server, not in the kernel. And since the kernel is in panic, the X
server can not run and can not do the mode switch.

I think there are patches to print panic messages to the frame buffer if
it is in use; but that still requires the X server to be configured to
use the kernel-provided frame buffer, and that can be quite slow (and it
also has other problems like not working on dual-head setups etc.)

Gabor

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     MTA SZTAKI Computer and Automation Research Institute
                Hungarian Academy of Sciences
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