What do you use for kernel debugging?

[O'Connor, Daniel]

On 1 Oct 2014, at 14:33, Adrian Chadd <adrian at freebsd.org> wrote:
> There's also something for XHCI.

So I see..

Section 7.6 in here has details..
http://www.intel.com.au/content/dam/www/public/us/en/documents/technical-specifications/extensible-host-controler-interface-usb-xhci.pdf

Interestingly unlike the EHCI version it does not require hardware between the debugger and debugee, only a special cable. (see http://msdn.microsoft.com/en-us/library/windows/hardware/hh439372(v=vs.85).aspx)

A quick search shows the cable is pretty cheap ($15 for a short one)

> Please please write it for freebsd. :)

Not sure I have the cycles :(

> 
> -a
> 
> 
> On 30 September 2014 21:45, O'Connor, Daniel <Daniel.O'Connor at emc.com> wrote:
>> 
>> On 1 Oct 2014, at 0:14, Julian Elischer <julian at freebsd.org> wrote:
>>> Unfortunately you can't use a USB serial as it requires the USB stack
>>> be  working before it can be used..
>>> similar with ethernet connected debugging which requires that the
>>> driver for the ethernet hardware support it.
>>> (which why we don't have it in the tree though it has been done
>>> several times in the past).
>> 
>> There IS a USB debug standard, Linux has some code to support it.
>> 
>> I am not sure what percentage of hardware has it hooked up though (the host controller has a designated debug port but it could physically be anything).
>> 
>> http://www.coreboot.org/EHCI_Debug_Port
>> 
>> The hardware is bit more expensive than a null modem or firewire cable though :(
>> 
>> Regards,
>>        Daniel O’Connor
>> 
>> Senior Software Engineer
>> Isilon Platforms Team
>> 
>> 
>> 
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Regards,
	Daniel O’Connor

Senior Software Engineer
Isilon Platforms Team