Re: Kernel Debugging Support

[Valdis.Kletnieks@vt.edu]

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On Mon, 04 Aug 2014 19:07:53 -0000, Paul Zimmerman said:

> Are you sure about that? Last I heard, xHCI debug support was a logo
> requirement from Microsoft for Windows 8 and above, so I would have
> thought that most vendors would have implemented it by now.

There's a lot of gear out in the real world that was manufactured before
Windows 8 was released.

And the actual requirement, as listed at:

http://msdn.microsoft.com/en-us/library/windows/hardware/jj128256

doesn't actually require USB debug -it requires a debug port, and xHCI
is below ethernet on the preference list.  As it says:

---
The next version of Windows will support several different debug transports.
They are listed below in the preferred order of implementation.

Hardware Debugging Transports

Ethernet Network Interface Card from the supported list: http://msdn.microsoft.com/en-us/library/windows/hardware/hh830880

USB 3.0 - xHCI controller compliant to xHCI debug specification.

1394 OHCI compliant Firewire controllers.

USB2 OTG (on supported hardware for Windows, recommend XHCI debug instead).

USB 2.0 EHCI debug (the debug enabled port must be user accessible). Legacy Serial (16550 compatible programming interface).

 ADDITIONAL REQUIREMENTSFOR ALL OF THE ABOVE IMPLEMENTATIONS THE FOLLOWING MUST APPLY:

There must be at least one user accessible debug port on the machine. It is
acceptable on systems which choose to not expose a USB port or any other
acceptable port from the list above to instead require a separate debugging
board or device that provides the ability to debug via one (or more) of the
transports above. That device/board must terminate in the same standard port as
would be used for the transport if it were \u2018onboard\u2019 the machine. If
this device is required it must be documented in the system specifications, be
user serviceable, be user installable on the machine, and available for sale
from the machine\u2019s vendor.


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