Re: Kernel Debugging Support

[Nick Krause]

On Mon, Aug 4, 2014 at 5:55 PM, Paul Zimmerman
<Paul.Zimmerman@xxxxxxxxxxxx> wrote:
>> From: Valdis.Kletnieks@xxxxxx [mailto:Valdis.Kletnieks@xxxxxx]
>> Sent: Monday, August 04, 2014 1:28 PM
>>
>> On Mon, 04 Aug 2014 19:40:15 -0000, Paul Zimmerman said:
>>
>> > Ah, you didn't read far enough down the page :)
>>
>> I'm willing to bet a large pizza with everything but anchovies that
>> out in the real world, a lot of implementors didn't read further either. :)
>
> Nah, I won't take that bet :)
>
>> > So I have to believe there are a *lot* of systems out there that do support xHCI debug.
>>
>> Possibly. But enough to make an actual critical mass to motivate somebody
>> to write code? Or do you get more bang-for-buck by fixing kgdb to support
>> debugging over Ethernet?
>
> Well, code to support the xHCI debug capability has been written, see
> http://marc.info/?l=linux-usb&m=135948845511047. But I did not get
> approval from my management to spend the time needed to integrate this
> into the kernel's kgdb support.
>
> Nick, if you are still interested in this, you could take a look at the
> above code, and see if you can work out how to modify it to make it work
> with kgdb. But you will need a PC that has a debug-capable xHCI
> controller in order to test it. If you have PC or laptop with USB 3.0
> built-in that has the Windows 8 logo, I think there's a good chance you
> already have one. Or, according to
> http://pete.akeo.ie/2011/08/do-necrenesas-upd720200-based-usb-30.html,
> plug-in USB 3.0 host cards that use the newer Renesas uPD720201 chipset
> also have the debug capability.
>
> Note that the above patch is against a pretty old kernel (3.6), so the
> first thing you would need to do is forward-port it to work on the
> latest kernel. As a plus, that would give you some real experience
> working with kernel code, which everyone seems to agree you need ;)
>
> --
> Paul
>

Paul ,
My computer is rather old now as of Sandy Bridge days, so I probably
can't test the patch
on my own machine. However I will look at the code and see if I can
forward port it
against the usb git tree I have a current version of. In addition I
would like the new xhci
maintainers information in  order to send out a patch with the
Maintainer for xhci updated.
Regards Nick
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