- Remove power to USB port
- Posted by dforster on February 18th, 2005
I am currently using CM_Request_Device_Eject to safely disconnect a USB
device. I would like to know if it possible to programatically shut down a
USB port so that the device no longer sees 5 volts on the connection. I
guess another way to say this would be, is it possible to simulate a physical
unplugging of the device?
Thanks for any help you can offer.
Dan
- Posted by 440gtx@email.com on February 20th, 2005
You can do this from user mode using the setup API's to disable the
device (StateChange=DICS_DISABLE). It might also be handy to know you
can simulate a unplug plus immediate replug from a driver using
IOCTL_INTERNAL_USB_CYCLE_PORT.
- Posted by dforster on February 22nd, 2005
When I disable the device, although Windows no longer recognizes the device
as being plugged in, the port is not actually disabled. By this I mean that
5 Volts is still present on the USB connector. I need to be able to
completely disable the port so that 5 Volts is no longer supplied to the
device.
"440gtx@email.com" wrote:
- Posted by Marc Reinig on March 2nd, 2005
In general, you cannot rely on USB ports having individual voltage controls.
Marco
________________________
Marc Reinig
UCO/Lick Observatory
Laboratory for Adaptive Optics
"dforster" <dforster@discussions.microsoft.com> wrote in message
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