Here is the text of the reference ticket that I opened with Garmin; I am wondering if anyone here can have ideas for a workaround / can verify that you see the same behavior? (I will post any updates from them here, as long as they just say that they cannot guarantee that the engineering department will do if anything)
The workaround zadig / WinUSB is not suitable for this application, due to the need for user interaction; we would like to find a solution or workaround that will just work out of the box.
In Windows Vista 32 home basic, the chrome USB API will not open the USB connection with the Garmin 60CSx, which uses the latest grmnusb driver (v2.3.1).
This can be seen with the USB Device Information Chrome app: https://chrome.google.com/webstore/detail/igkmggljimacfdfalpeelenjeicmfnll
However, if you change this device to use the WinUSB driver instead, reboot it, you can open it with this chrome application and other applications that use the chrome USB interface.
I used the "zadig" program to change this driver as suggested in this thread: https://code.google.com/p/chromium/issues/detail?id=249908
And if I then use the device manager to "Rollback the driver", so that grmnusb is again the only driver for 60CSx, then, as expected, it will not open again in the Chrome application.
So, I think the problem was isolated from the fact that grmnusb is not compatible with the USB API chrome interface. I believe this is a bug in grmnusb. Can I change it to work with Chrome’s USB interface? Thanks
UPDATE 6-23-15: no real news, but confirmation from other application developers that this is exactly how the Windows drivers work: the grmnusb driver “owns” this USB device and nothing else can talk to this device through USB But it turns out that I completely skipped the Garmin interface document section, which says that you need to use the Win32 API calls to talk to the driver. All this definitely clarifies things: now the problem is to find the easiest way for the browser to talk to the driver; It seems that the easiest way could be to create your own Windows application that makes Win32API calls, as well as create your own messages with the Chrome extension to transfer data to / from a web page. Any new entry would be greatly appreciated!