Ejecting a USB Device

NTDEV
1

All,
Several years ago we developed a USB driver using WDM. As part of a test
application, we have been using CM_Request_Device_Eject() to remove the
device. This worked quite nicely. We just recently ported the driver’s
functionality over to KMDF. Now when we call CM_Request_Device_Eject(), the
device does not get removed but instead it still appears in the Device
Manager with a yellow exclamation mark. When we display the Properties, we
see that the error code is 47 - the device has been prepared for safe
removal. Once the device is disconnected everything is cleaned up. Below are
a few data points:

  1. When CM_Request_Device_Eject() is being processed, the Exit DO and
    Release Hardware Event handles are both being called.
  2. In the AddDevice routine, we’re calling WdfDeviceSetPnpCapabilities with
    the following fields set to WdfTrue:
    SurpriseRemovalOk, Removable, EjectSupported, and SilentInstall. The rest of
    the filelds are set to the defaults used by the INIT macro.
  3. We’re observing this behaviour on 32-bit, Win7.

Any ideas of what could be going on here would be greatly appreciated.
TIA!

2

> see that the error code is 47 - the device has been prepared for safe

removal. Once the device is disconnected everything is cleaned up.

This is the same for inbox USBSTOR driver and flash disk devices.

–
Maxim S. Shatskih
Microsoft MVP on File System And Storage
xxxxx@storagecraft.com
http://www.storagecraft.com

3

Maybe so but this is not how our unclassified, WDM driver works. In that
case, when you eject the device via CM_Request_Device_Eject, the device
driver is gracefully removed and then re-enumerated. No hot plugging is
necessary. Makes for a *great* test bed. Thus we want that same behavior
with our KMDF driver.

On Fri, Sep 5, 2014 at 4:40 AM, Maxim S. Shatskih
wrote:

> > see that the error code is 47 - the device has been prepared for safe
> > removal. Once the device is disconnected everything is cleaned up.
>
> This is the same for inbox USBSTOR driver and flash disk devices.
>
> –
> Maxim S. Shatskih
> Microsoft MVP on File System And Storage
> xxxxx@storagecraft.com
> http://www.storagecraft.com
>
>
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