I downloaded VMWare Player today (4.0.4 build-744019), installed it on a Vista 64-bit computer, and am trying to get it setup to run DOS in the VM. I'm trying to test some DOS USB drivers, but VMWare won't let me enable the IRQ for the USB UHCI host contoller. In my case, that's IRQ 10, which is initially disabled after the VM boot.
Sending the approprioate value to the PIC (via I/O port A1h) to enable IRQ 10 is sometimes simply ignored (IRQ 10 stays disabled), and sometimes generates a GPF. Exactly which one happens seems to depend on whether the other parts of the UHCI controller (Frame List memory address, Run/Halt, etc.) are configured. I.e., if not configured, the IRQ enable request is simply ignored, and if the host is at least partially configured, a GPF is generated.
Any ideas?