If I have ehci enabled, my usb keyboard stops working once the ehci driver
is loaded. (Can type at boot prompt etc) With ehci commented out, all is OK:

uhidev0 at uhub3 port 1 configuration 1 interface 0
uhidev0: DELL DELL USB Keyboard, rev 1.10/1.04, addr 2, iclass 3/1
ukbd0 at uhidev0: 8 modifier keys, 6 key codes

with ehci:

ehci0 at pci0 dev 29 function 7: Intel 82801FB/FR USB EHCI Controller (rev. 0x03)
ehci0: interrupting at ioapic0 pin 21 (irq 9)
ehci0: EHCI version 1.0
ehci0: companion controllers, 2 ports each: uhci0 uhci1 uhci2 uhci3
usb4 at ehci0: USB revision 2.0
uhub4 at usb4
uhub4: Intel EHCI root hub, class 9/0, rev 2.00/1.00, addr 1
uhub4: 8 ports with 8 removable, self powered

but then just the mouse is seen on

uhidev0 at uhub3 port 2 configuration 1 interface 0
uhidev0: Dell Dell USB Mouse, rev 1.10/29.10, addr 2, iclass 3/1
ums0 at uhidev0: 3 buttons and Z dir.
wsmouse0 at ums0 mux 0

but no keyboard..

(Entertainingly this is true for Dell GX280 BIOS revisions A04 and the
lastest A06 which allegedly fixes USB troubles. A05 seems to work.)

How can I help?

Cheers,

Patrick