udev rule for matching USB class and subclass?

[Felipe Sateler]

On 11 October 2016 at 01:49, Petter Reinholdtsen <pere at hungry.com> wrote:
> [Felipe Sateler]
>> Yes the documentation is quite poor in this regard.
>
> I am glad I found you, then, to let me know about the MODALIAS
> attribute. :)
>
>> But, modalias may be even the wrong match. A usb thumb drive I have (I
>> don't have a smartcard reader) does not have a MODALIAS set (you can
>> see the properties with `udevadm info`), although there are
>> intermediate paths that do have it.
>
> Wow, I thought the kernel synthesized modalias fields for all hardware
> it knew about, and have never seen any USB unit where the kernel did not
> provide a modalias file.
>
>> What does `udevadm info` say about the device?
>
> For my test unit I get this:
>
> P: /devices/pci0000:00/0000:00:1a.0/usb1/1-1
> N: bus/usb/001/000
> E: BUSNUM=001
> E: DEVNAME=/dev/bus/usb/001/000
> E: DEVNUM=000
> E: DEVPATH=/devices/pci0000:00/0000:00:1a.0/usb1/1-1
> E: DEVTYPE=usb_device
> E: DRIVER=usb
> E: ID_BUS=usb
> E: ID_MODEL=Tenx_Nonstandard_Devic
> E: ID_MODEL_ENC=Tenx\x20Nonstandard\x20Devic
> E: ID_MODEL_FROM_DATABASE=Rocket Launcher
> E: ID_MODEL_ID=0202
> E: ID_REVISION=0100
> E: ID_SERIAL=1130_Tenx_Nonstandard_Devic
> E: ID_USB_INTERFACES=:030000:
> E: ID_VENDOR=1130
> E: ID_VENDOR_ENC=1130
> E: ID_VENDOR_FROM_DATABASE=Tenx Technology, Inc.
> E: ID_VENDOR_ID=1130
> E: MAJOR=189
> E: MINOR=1
> E: PRODUCT=1130/202/100
> E: SUBSYSTEM=usb
> E: TYPE=0/0/0
> E: USEC_INITIALIZED=671889072
>
> And /sys/devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1:1.0/modalias
> contain usb:v1130p0202d0100dc00dsc00dp00ic03isc00ip00in00.
>
> I'm testing using my USB Rocket Launcher to use USB unit that is not
> handled by any of the packages I need to have installed on my machine.

That suggests that for some reason udev is not importing the modalias
into the environment. I have no idea why that would be the case.

-- 

Saludos,
Felipe Sateler