RE: Kernel Debugging Support

[Paul Zimmerman]

> 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