remote debug over usb vs. old serial cable?

[Andriy Gapon]

on 26/03/2009 15:06 Erik Trulsson said the following:
> On Thu, Mar 26, 2009 at 01:56:13PM +0100, Ronald Klop wrote:
>> Hello,
>>
>> In the past I could catch a panic during boot via a serial cable connected  
>> to another computer.
>> My new computer only has USB-ports and ethernet. What kind of cable do I  
>> need now to do remote debugging?
>> The old computer also has usb, so I think the connection should be in that  
>> corner.
>> They all run 7-STABLE.
> 
> USB won't work for that purpose.  It requires far too much kernel support to
> be useful after a panic.

Erik,
in fact, there is a special USB (EHCI) mode for such purposes:
http://www.coreboot.org/EHCI_Debug_Port

But that requires some special HW in addition to SW support which our doesn't have.

BTW, Ronald, it is possible that you might have a serial header on motherboard
which is not connected to any traditional port.

-- 
Andriy Gapon