I’m working with a cypress FX2 USB based device, using sample code from
them for drivers that interface with the USBD bus driver. When my device
provides a serial number in the string descriptor field, a system-supplied
symbolic link appears that is unique for every serial-numbered device that
is connected to the USB ports on the system. There is a GUID concatenated
on the end of the symbolic link.
When I use this symbolic link to connect my app to the device, I find that
at least one system in my lab gives a -1 return value from CreateFile (an
IBM thinkpad T23) but only via the USB2.0 interface, not the USB1.1. Are
there some security attributes I need to verify or change when using this
symbolic link?
Where does the GUID come from that gets concatenated to this symbolic
link, and how can I predict when it will change on me, so that the
application can still connect to the device?
Thanks for any help,