Safe removal of USB device

  • Thread starter Thread starter Sobhan Vezzu
  • Start date Start date
S

Sobhan Vezzu

Hello All:

We are developing a USB hardware device which will have a soft eject
option from the device. So when user presses the button we will do a
soft eject but the device is till connected. But we are unable to make
OS recognise the device again? Any inputs on this will be appreciated.



Thanks,
Sobhan
 
don't have a clue as to the how, but the thought occurs to trigger a
device manager refresh.

Beverly Howard [MS MVP-Mobile Devices]
 
don't have a clue as to the how, but the thought occurs to trigger a
device manager refresh.

Beverly Howard [MS MVP-Mobile Devices]
Click to expand...

We have tried this but it does not work.
 
Sobhan said:
Hello All:

We are developing a USB hardware device which will have a soft eject
option from the device. So when user presses the button we will do a
soft eject but the device is till connected. But we are unable to make
OS recognise the device again? Any inputs on this will be appreciated.
Click to expand...

There is the DeviceIoCall IOCTL_USB_HUB_CYCLE_PORT which is
documented to simulate a replug of the usb device. But there
are reports that it does not power cycle the USB port. Maybe
because the USB hubs and root hubs are not able to switch the
power of specific USB ports.
A solution would be to put an USB hub before the device
in question and deactivate + reactivate it. This wakes
up devices which had been prepared for safe removal.


Greetings from Germany

Uwe
 
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