Hi folks,
this is a followup to my earlier query about USB 3 ports failing on Windows
7. I've confirmed that the failures I see are due to bugs in the USB 3 port
drivers, which don't support the IOCTL_USB_GET_NODE_CONNECTION_INFORMATION_EX
or IOCTL_USB_GET_DESCRIPTOR_FROM_NODE_CONNECTION ioctls.
I believe it's possible to work around these bugs for WinUsb-backed devices
by reading the info from WinUsb instead of these ioctls. A couple hiccups:
1. It's possible to read the device descriptor for a device, but this
doesn't provide all the information in USB_NODE_CONNECTION_INFORMATION_EX.
I didn't find any use being made of a lot of the info that's in there, e.g.
the pipe info. The bus-relative device address produces a warning for me if
I leave it unset, but I don't know whether apps will break if it's left
uninitialized. Thoughts?
2. Determining when to call WinUsb is a little bit of a challenge. The
ioctls are currently done in init_device, during GEN_PASS, but the driver
isn't read until DEV_PASS, so we don't know yet whether a device is a
WinUsb device. Is it reasonable to postpone reading the device and config
descriptors until DEV_PASS, when we know the device is a WinUsb device?
Thanks,
--Juan
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