[Nut-upsdev] newhidups subdriver_matcher incorrectly matches USB hub

[Schmier, Jacob]

I ran into the following issue today and would like some feedback from
the group.

Setup:
I am using a MGE Pulsar Evolution 2200 UPS connected through a Belkin
(F5U218-MOB) 4-Port USB Hub.

Scenario:
The newhidups subdriver_matcher function calls
belkin_subdriver->belkin_claim. The belkin_claim function in
belkin-hid.c matches the VendorID of the hub to Belkin's VendorID
(0x050d), causing the hub to be recognized as a UPS. The newhidups
driver (libusb.c) then attempts to claim the device and detatches the
kernel driver. When the hub fails to provide a HID descriptor, the
newhidups driver moves on to the next device and correctly locates the
MGE UPS. The problem is that the hub is now non-functional as the hub
kernel driver has been detatched. 

Problem:
The belkin_claim function should not assume that because the VendorID is
Belkin's the device is a UPS. Belkin makes several USB devices and
starting newhidups with them connected could leave them inoperable until
they are removed an reconnected.  Even if the UPS is not connected
through the hub, the hub can still get disabled if it is matched before
the UPS.

If MGE made a USB hub, the mge_claim function in mge-hid.c would have
the same issue.


Output:

:/tmp# /tmp/newhidups -DDD /dev/usb/hid/hiddev0
Network UPS Tools: New USB/HID UPS driver 0.28 (2.0.4)

debug level is '3'
Checking device (0000/0000) (001/001)
- VendorID: 0000
- ProductID: 0000
- Manufacturer: unknown
- Product: USB OHCI Root Hub
- Serial Number: c64ffc00
- Bus: 001
Trying to match device
Device does not match - skipping
Checking device (050D/0218) (001/014)
- VendorID: 050d
- ProductID: 0218
- Manufacturer: unknown
- Product: unknown
- Serial Number: unknown
- Bus: 001
Trying to match device
Device matches
failed to claim USB device, trying 2 more time(s)...
detaching kernel driver from USB device...
trying again to claim USB device...
Unable to get HID descriptor (error sending control message: Broken
pipe)
Checking device (0463/FFFF) (001/015)
- VendorID: 0463
- ProductID: ffff
- Manufacturer: MGE UPS SYSTEMS
- Product: Evolution
- Serial Number: AH2G10067
- Bus: 001
Trying to match device
Device matches
HID descriptor retrieved (Reportlen = 1620)
Size read for the report descriptor: 1620
Report descriptor retrieved (Reportlen = 1620)
Found HID device
Report Descriptor size = 1620
Report Descriptor: (200 bytes) => 05 84 09 04 A1 01 09 10 A1 00 85 01 09
11 75 08
Detected a UPS: MGE UPS SYSTEMS/Evolution
Using subdriver: MGE HID 0.9
......cut......



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