Port 1 of USB EHCI controller is not physically exposed, how to expose it, to debug
Yes, LAN debug is Windows 8 only. And like Don said, it's quite common USB port
1 is not physically accessible. There may not be able any way to do kernel
debugging on some machines. For Windows 8 I believe one of the certification
tests now requires there be a way to do kernel debugging.
A thing laptops sometimes do have is an internal mini PCIe slot, and I believe
I've seen cables than can plug into this connector that let you plug a normal 1x
PCIe card into. This might allow using 1394 debugging on laptops with a
mini-PCIe slot. A quick google search actually says startech makes a mini-PCIe
If you're a hardware type, the south bridge chip often has a legacy serial port
on the internal LPC bus, and in theory you could connect a logic level (i.e.
3.3V not RS232 12V) serial dongle to the chipset pins, even if these pins are
normally not externally exposed. I've never done this personally but once
considered the idea and it seems possible with the right board skills (soldering
surface mount, or using micro grabber clips). The board manufacturer also may
have already brought the chip pins to some pads in a 10 pin header pattern and a
drill and solder is all that's needed to make them accessible (you still need a
logic level to USB serial dongle, but they exist). Having a few extra PCB traces
costs essentially nothing per systems, but adding the connector does, so is left
off production systems.
Some laptops (pretty rare now) do have cardbus/expresscard slots which you can
get 1394 cards for.
Is there some reason you can't do the debugging under Win 8, as it does add
other debugger transports, like some NICs and USB 3.
My experience of USB 2 debugging has been it essentially doesn't work. I've seen
USB 2 debugger connections run for 10 minutes, but I've NEVER successfully used
one for real work.
A few tips I heard to help USB debugging, which I haven't tried: be sure to use
the busparams option to select a specific chip and turn off ALL use of USB from
the bios (things like settings for USB legacy support).
If you have lots of cash, I believe there are debuggers that connect via the
processor socket. It's been years since I used one of these, and a while ago
they cost like $50,000+. How bad do you want to debug THAT machine.
From: email@example.com [mailto:firstname.lastname@example.org] On Behalf Of
Sent: Saturday, July 07, 2012 4:39 AM
To: Kernel Debugging Interest List
Subject: [windbg] Port 1 of USB EHCI controller is not physically exposed, how
to expose it, to debug
Recently I purchased one board of Gigabyte
Model : GA-Z77M-D3H
BIOS : American Megatrends
BIOS Version : F7
BIOS ID : 8A01AG0L
I gone through all the settings of USB debug for both Target and Host system
with USB 2.0 debug cable.
But when I reached to USB View page , the port 1 of USB 2.0 EHCI controller is
not coming or not physically exposed.
So how to enable or expose port 1 of USB EHCI controller, as explained in all
the document of USB debug. Like
Where I?m wrong don?t know, but till now what I understand is that might be
there is a problem with my BIOS,
So please suggest me the best way to start the Windows Driver debugging through
USB 2.0 debug cable.
Else is there any other best known method, but I have system with USB only as
one is Laptop and that to without any null modem & 1394 port.
Thus I must have to use USB debug only. I don?t want to go for Lan debug and I
think Windows 8 is require for that.
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