EHCI USB on _top_ of UHCI?

I'm running 5.1-RELEASE and have USB2.0 ports in my Dell D800 laptop.
I also have a USB2.0 drive encloseure with a 120G drive in it... so
I'm very motivated to get this to work :).

To start, I posted briefly about this before... and some people
suggested that this may have a bad interaction with ACPI.  I have
ruled that out ... disabling ACPI or fixing ACPI (by obtaining fixed
ACPI code) doesn't change the EHCI behaviour.

So ... some datapoints.  USB 1.1 (UHCI) works.  If EHCI isn't in the
kernel all manner of USB devices work.  I have tested the drive, an
external DVD enclosure and a mouse.  This is good.

However, if EHCI is in the kernel, attaching the drive gives the
following messages:

Jun 13 22:15:46 canoe kernel: usb3: unrecoverable error, controller halted
Jun 13 22:15:46 canoe kernel: usb3: blocking intrs 0x10
Jun 13 22:16:05 canoe kernel: uhub3: device problem, disabling port 3
Jun 13 22:16:48 canoe kernel: usb3: port reset timeout
Jun 13 22:16:48 canoe kernel: uhub3: port 1 reset failed

... and then usb doesn't work thereafter.  Is this something that's
fixable?  I'm willing to do some work on this, but I'm a little at a
loss on where to start.  I intend to track -CURRENT with this laptop,
but my attempt to move from 5.1-RELEASE to -CURRENT was stymied by
source that wouldn't compile.

For reference, here are all the USB related probe lines with EHCI
compiled into the kernel:

Jun 13 21:51:04 canoe kernel: uhci0: <Intel 82801DB (ICH4) USB controller USB-A> port 0xbf80-0xbf9f irq 11 at device 29.0 on pci0
Jun 13 21:51:04 canoe kernel: usb0: <Intel 82801DB (ICH4) USB controller USB-A> on uhci0
Jun 13 21:51:04 canoe kernel: usb0: USB revision 1.0
Jun 13 21:51:04 canoe kernel: uhci1: <Intel 82801DB (ICH4) USB controller USB-B> port 0xbf40-0xbf5f irq 11 at device 29.1 on pci0
Jun 13 21:51:04 canoe kernel: usb1: <Intel 82801DB (ICH4) USB controller USB-B> on uhci1
Jun 13 21:51:04 canoe kernel: usb1: USB revision 1.0
Jun 13 21:51:04 canoe kernel: uhci2: <Intel 82801DB (ICH4) USB controller USB-C> port 0xbf20-0xbf3f irq 11 at device 29.2 on pci0
Jun 13 21:51:04 canoe kernel: usb2: <Intel 82801DB (ICH4) USB controller USB-C> on uhci2
Jun 13 21:51:04 canoe kernel: usb2: USB revision 1.0
Jun 13 21:51:04 canoe kernel: ehci0: <EHCI (generic) USB 2.0 controller> mem 0xf4fffc00-0xf4ffffff irq 11 at device 29.7 on pci0
Jun 13 21:51:04 canoe kernel: ehci_pci_attach: companion usb0
Jun 13 21:51:04 canoe kernel: ehci_pci_attach: companion usb1
Jun 13 21:51:04 canoe kernel: ehci_pci_attach: companion usb2
Jun 13 21:51:04 canoe kernel: usb3: EHCI version 1.0
Jun 13 21:51:04 canoe kernel: usb3: companion controllers, 2 ports each: usb0 usb1 usb2
Jun 13 21:51:04 canoe kernel: usb3: <EHCI (generic) USB 2.0 controller> on ehci0
Jun 13 21:51:04 canoe kernel: usb3: USB revision 2.0

Dave.

-- 
============================================================================
|David Gilbert, Velocet Communications.       | Two things can only be     |
|Mail:       dgilbert_at_velocet.net             |  equal if and only if they |
|http://daveg.ca                              |   are precisely opposite.  |
=========================================================GLO================