Do you have "always enable USB" set in the machine policy? Try reversing the option, maybe it's a buggy bios.
Out of curiousity... Does the touchscreen work during preboot on the XPS12?
We are looking at getting some & would be nice if this is supported (our Samsung Slates don't support Touch in the UEFI boot unfortunately)
I'll be able to answer my own question soon. I've got a dell xps12 eval unit for the next few weeks. Will post once i get it encrypted to let you know if my keyboard/touchpad work during pre-boot & also if touch screen works.
I suspect touchscreen will work, as after updating the uefi firmware & using the mcafee uefi test utility the touchscreen was working (didn't prior to firmware upgrade). It was a little weird as the touchscreen was scaled to the full screen size, however the test application was only scaled to a quarter of the screen (so I had to touch the blank corners rather than the red buttons, other than the top left button which was in the top left corner).
How did you go with this?
I've got my hands on a XPS12 and i'm getting the same problem. But in addition to that even the external keyboard isn't working sometimes...
If the external keyboard works, so does the touchscreen... If the external keyboard is not working, neither does the touchscreen.... I'm wondering if the pre-boot environment is actually hanging?
i've tried "always enable USB" enabled & disblaed, keyboard and trackpad doesnt work on either setting.
I've worked out more on the touchscreen thing too... if i press f12 to get boot options & select the internal disk, the touchscreen works at preboot; otherwise it doesnt work. Keyboard and trackpad dont work in either case.
Touchscreen works in the UEFI EETECH Standalone and also the McAfee UEFI Touch Test tool, but that just supports that going to the F12 boot menu before booting to anything keeps the TouchScreen working with the McAfee products... (again, keyboard/trackpad not working in these environments).
Unsure if this is a McAfee problem or a Dell problem?
The USB settings only affect the BIOS version of EEPC, the uEFI one relies on the manf provided UEFI environment having support for the absolute and simple pointer protocols. Without those, the EEPC UEFI software cannot "see" the touchscreen or mouse.
These are essential parts of the Ultrabook standard.
The UEFI environment obviously does have support for the protocols as it all (EEPC Pre-Boot, EETECH Standalone, McAfee UEFITabletTool) works fine when booting via the F12 boot menu. Its only when booting directly (i.e. not manually specifying the harddisk) that it doesn't work.
As mentioned above, the keyboard & trackpad don't work in any case...
I've got a case open with Dell, but it is not looking very promising either...
Regarding the touchscreen not working during pre-boot, that is actually how it should be. As touch screens are depending on software to function, it will only work once the system has boot into Windows.
As for the keyboard and touchpad, do you mean that they are not working in preboot but works after booting into Windows?
Maybe this is a sign that UEFI is just too 'new' still and we'll be force back to using legacy BIOS instead...
I've managed to get the support case with Dell escalated to someone who can work with their Tier 3 & Engineering.
Its very strange though, even in Legacy BIOS mode the keyboard, trackpad & USB devices work only under certain conditions.... i.e. on a clean start up (from powered off), it all works (minus touch screen obviously), however after a reboot *only* the keyboard will work, USB devices & trackpad do not...
Also with UEFI, if you boot to the McAfee Tablet Tool without using F12 boot menu, the touchscreen works...
I'm thinking we might need Dell & McAfee to work together to try to work this out...