use the driver field from parent node is wrong for certain usb node

[Yuan-Chen Cheng]

Per investigation, in

https://git.launchpad.net/checkbox-support/tree/checkbox_support/parsers/udevadm.py#n583

it use the driver value from parent.

For node like

/devices/pci0000:00/0000:00:14.0/usb1/1-1/1-1:1.0

if driver is missing, then it does not have driver loaded. However, above code still use the value from parent, which is wrong.

For node like

/devices/pci0000:00/0000:00:14.0/usb1/1-13/1-13:1.0/0003:046D:C534.0011

check the driver of parent is correct.

[Yuan-Chen Cheng (ycheng-twn)]

the output of udev_resource.py.

Note
1. I change the output of vid/pid into hex, check https://code.launchpad.net/~ycheng-twn/plainbox-provider-resource/+git/plainbox-provider-resource/+merge/388983
2. usb vid 27c6, pid: 533c driver is not loaded.

[Yuan-Chen Cheng (ycheng-twn)]

raw output of udevadm-info--export-db

[Yuan-Chen Cheng (ycheng-twn)]

raw output of lsblk for above test.

[Yuan-Chen Cheng (ycheng-twn)]

the usb device in above example is a finger print usb device.

Per what I know, even it works, it's drives by user space driver.

The reason I dig into this, is to have a test case to list device node
without kernel module loaded.

[Sylvain Pineau (sylvain-pineau)]

Then definitely using the checkbox support udev parser for that type of check is a bad idea.
I'd try to develop a test that specifically checks for a missing driver if that's the goal.
For fingerprint readers, if the driver is not loaded then the corresponding certification test should fail.