With respect to the following commits:

df0b344 drm/usb: select USB_SUPPORT in Kconfig 8f057d7 gpu/mfd/usb: Fix USB randconfig problems

... which end up with the following in next-20120904:

config DRM_USB depends on DRM depends on USB_ARCH_HAS_HCD select USB select USB_SUPPORT

config DRM_UDL depends on DRM && EXPERIMENTAL depends on USB_ARCH_HAS_HCD select DRM_USB

Surely this is backwards; these should be dependencies, not selects? In other words:

config DRM_USB depends on DRM && USB

config DRM_UDL depends on DRM && EXPERIMENTAL && USB select DRM_USB

or perhaps:

config DRM_USB depends on DRM && USB

config DRM_UDL depends on DRM && EXPERIMENTAL && DRM_USB

The problem here is that currently, the dependency logic for USB:

config USB depends on USB_ARCH_HAS_HCD

... is duplicated into each of DRM_USB and DRM_UDL, thus requiring both of those to be edited should the dependencies for USB ever change.

The current state of the code also causes some strange problem with ARM's tegra_defconfig, whereby running "make tegra_defconfig" will result in USB support fully enabled in .config as expected, yet subsequently running "make oldconfig" will cause all USB support to be removed from .config. For some reason, the above DRM logic is causing CONFIG_USB_ARCH_HAS_HCD not to be selected (perhaps it isn't evaluated because USB is selected, so there's no need to evaluate USB's dependencies?). Arguably, this is a deficiency in Tegra's Kconfig, in that it probably should say:

select USB_ARCH_HAS_EHCI

not:

select USB_ARCH_HAS_EHCI if USB_SUPPORT

... but it has contained the latter for quite some time, and it's always worked before somehow.