Kexec not working as expected from inside X

David N. Lombard dnlombar at
Mon Nov 30 09:50:10 EST 2009

On Mon, Nov 30, 2009 at 12:57:40AM -0700, Bernhard Walle wrote:
> Mayank Kaushik schrieb:
> >
> > Is it something in the nvidia driver that's causing this to not work?
> > Any clues on what's going wrong, or how I can debug this further?
> You should attach a serial console to debug that. Is that possible on
> your system. It's also possible to use a USB-to-RS232 converter on the
> machine that should be debugged. However, that only works after the USB
> drivers have been loaded, so much later than a real serial console.

A normal serial console will do for this particular task, but when you need
very early debugging, there's also a "USB debug" cable.  AFAICT, this is a
sole-source item from Ajays Technology and only sold at

See Documentation/x86/earlyprintk.txt on using the device...

It's on my XMAS wish list ;)

David N. Lombard, Intel, Irvine, CA
I do not speak for Intel Corporation; all comments are strictly my own.

More information about the kexec mailing list