Re: debugging a modern laptop ...

From: Mark Lord
Date: Wed Mar 23 2011 - 11:16:17 EST

On 11-03-23 11:04 AM, Alan Stern wrote:
> On Wed, 23 Mar 2011, Herbert Poetzl wrote:
>> Greetings!
>> I'm trying to evaluate my options on debugging a recent
>> laptop/notebook/table (and the Linux kernel on it of course)
>> from early bootup to diagnostics when the machine has locked up ...
> There _is_ support for a USB console (see CONFIG_USB_SERIAL_CONSOLE).
> However it may not be useful for diagnosing problems during boot,
> because obviously the console won't operate until the USB stack is in
> place and running.

If you are lucky enough to have an ExpressCard slot on the notebook,
then lots of eBay sellers offer "Oxford chipset" serial/parallel ports
in ExpressCard format.

These provide "true" bus serial ports, which can be used as Linux consoles
for low level kernel debugging, logs, panics, etc..

As a bonus, he parallel ports from the same chips can be used
for homebrew JTAG adapters.

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