usbd_attach() from more than one driver

Hi,

we developing a Device Firmware Upgrade(DFU) driver which is describe in the a USB Class Specification, and we use the last USB DDK
for QNX 6.0 RtP.
In the Class Specification is describe that every Device that supports DFU must have a special DFU Interface Descriptor with no
Endpoint Descriptors because DFU uses only the control endpoint for comunication.
On run-time the normal device driver is already “attached” to the device, so that another usb_attach() will fail if we try to
“attach” the device in the insertion function. Therefore we can´t do any usbd_io() to the DFU device on run-time, or is it possible
to comunicate over the control endpoint without a usbd_attach()?


Thank you.

Hermann Leenings

Hermann Leenings <Leenings.Hermann@scheidt-bachmann.de> wrote:

Hi,

we developing a Device Firmware Upgrade(DFU) driver which is describe in the a USB Class Specification, and we use the last USB DDK
for QNX 6.0 RtP.
In the Class Specification is describe that every Device that supports DFU must have a special DFU Interface Descriptor with no
Endpoint Descriptors because DFU uses only the control endpoint for comunication.
On run-time the normal device driver is already “attached” to the device, so that another usb_attach() will fail if we try to
“attach” the device in the insertion function. Therefore we can’t do any usbd_io() to the DFU device on run-time, or is it possible
to comunicate over the control endpoint without a usbd_attach()?

You can attach to the device in non-exclusize mode by not passing the
callback functions to usbd_connect.