[$] Driver regression testing with roadtest

The kernel community has a number of excuses for the relative paucity ofregression-test coverage in the project, some of which hold more water thanothers. One of the more convincing reasons is that a great deal of kernelcode is hardware-specific, and nobody can ever hope to put together atesting system with even a small fraction of all the hardware that thekernel supports. A new driver-testing framework called roadtest,posted by Vincent Whitchurch, may make that excuse harder to sustain,though, at least for certain kinds of hardware.