We observed a new behaviour in Vista RC1/RC2 for a device disable within the device manager – with all older WDM based OS versions the USB device gets suspended if the driver gots disabled. Starting with Vista we are missing the USB suspend. We checked this on various systems and USB 1.1/2.0 host controllers using always only one device.
In order to exclude any problem with our own devcie/driver we confirmed the very same behaviour for standard USB mass storage devices as well. So even the USB mass storage class driver from Microsoft is not suspending a USB storage device.
Anybody any idea why this has changed? In the end (buspowered) devices consume much more power without a USB suspend.
Thanks,
Diego