Re: Kernel Debugging Support

[Nick Krause]

On Mon, Aug 4, 2014 at 7:03 PM, Paul Zimmerman
<Paul.Zimmerman@xxxxxxxxxxxx> wrote:
>> From: Nick Krause [mailto:xerofoify@xxxxxxxxx]
>> Sent: Monday, August 04, 2014 3:50 PM
>>
>> 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.
>
> Sarah already told you who the new maintainer is, and then CCed him
> on this thread. Hint: There is a file name 'MAINTAINERS' in the root
> of the kernel tree, which tells you who the maintainers are for all of
> the subsystems. Please read Documentation/SubmittingPatches, it has a
> lot of information like this that you need to know.
>
> --
> Paul
>
Thanks I will read this file and thanks for the information. I known
where the file is I will
add the information then.
Regards Nick
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