udev rule with bInterfaceNumber doesn't work
I'm trying to use udev to give relevant names a USB-serial device but I'm having now luck.
# lsusb -d 04e2:1412 -v
Bus 004 Device 028: ID 04e2:1412 Exar Corp.
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 2.00
bDeviceClass 239 Miscellaneous Device
bDeviceSubClass 2 Common Class
bDeviceProtocol 1 Interface Association
bMaxPacketSize0 64
idVendor 0x04e2 Exar Corp.
idProduct 0x1412
bcdDevice 0.02
iManufacturer 0
iProduct 0
iSerial 0
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 141
bNumInterfaces 4
bConfigurationValue 1
iConfiguration 0
bmAttributes 0xa0
(Bus Powered)
Remote Wakeup
MaxPower 94mA
Interface Association:
bLength 8
bDescriptorType 11
bFirstInterface 0
bInterfaceCount 2
bFunctionClass 2 Communications
bFunctionSubClass 2 Abstract (modem)
bFunctionProtocol 0 None
iFunction 0
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 1
bInterfaceClass 2 Communications
bInterfaceSubClass 2 Abstract (modem)
bInterfaceProtocol 1 AT-commands (v.25ter)
iInterface 0
CDC Header:
bcdCDC 1.10
CDC ACM:
bmCapabilities 0x06
sends break
line coding and serial state
CDC Union:
bMasterInterface 0
bSlaveInterface 1
CDC Call Management:
bmCapabilities 0x01
call management
bDataInterface 1
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x85 EP 5 IN
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 2
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 1
bAlternateSetting 0
bNumEndpoints 2
bInterfaceClass 10 CDC Data
bInterfaceSubClass 0 Unused
bInterfaceProtocol 0
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x01 EP 1 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 0
Interface Association:
bLength 8
bDescriptorType 11
bFirstInterface 2
bInterfaceCount 2
bFunctionClass 2 Communications
bFunctionSubClass 2 Abstract (modem)
bFunctionProtocol 0 None
iFunction 0
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 2
bAlternateSetting 0
bNumEndpoints 1
bInterfaceClass 2 Communications
bInterfaceSubClass 2 Abstract (modem)
bInterfaceProtocol 1 AT-commands (v.25ter)
iInterface 0
CDC Header:
bcdCDC 1.10
CDC ACM:
bmCapabilities 0x06
sends break
line coding and serial state
CDC Union:
bMasterInterface 2
bSlaveInterface 3
CDC Call Management:
bmCapabilities 0x01
call management
bDataInterface 3
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x86 EP 6 IN
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 2
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 3
bAlternateSetting 0
bNumEndpoints 2
bInterfaceClass 10 CDC Data
bInterfaceSubClass 0 Unused
bInterfaceProtocol 0
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x02 EP 2 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x82 EP 2 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 0
Device Status: 0x0000
(Bus Powered)
The udev rules I'm trying are:
KERNEL=="ttyUSB[0-9]*", SUBSYSTEMS=="usb", ATTRS{bInterfaceNumber}=="01", ATTRS{idVendor}=="04e2", ATTRS{idProduct}=="1412", ACTION=="add", SYMLINK+="test_USB0"
KERNEL=="ttyUSB[0-9]*", SUBSYSTEMS=="usb", ATTRS{bInterfaceNumber}=="01", ATTRS{idVendor}=="04e2", ATTRS{idProduct}=="1412", ACTION=="add", SYMLINK+="test_USB1"
KERNEL=="ttyUSB[0-9]*", SUBSYSTEMS=="usb", ATTRS{bInterfaceNumber}=="02", ATTRS{idVendor}=="04e2", ATTRS{idProduct}=="1412", ACTION=="add", SYMLINK+="test_USB2"
KERNEL=="ttyUSB[0-9]*", SUBSYSTEMS=="usb", ATTRS{bInterfaceNumber}=="03", ATTRS{idVendor}=="04e2", ATTRS{idProduct}=="1412", ACTION=="add", SYMLINK+="test_USB3"
When I use only the first udev rule without the bInterfaceNumber attribute, like so:
KERNEL=="ttyUSB[0-9]*", SUBSYSTEMS=="usb", ATTRS{idVendor}=="04e2", ATTRS{idProduct}=="1412", ACTION=="add", SYMLINK+="test_USB0"
It works ok. I can see symbolic link /dev/test_USB0 created which points to /dev/ttyUSB0 but what about the other ttyUSB devices created when I plug in this usbserial device?
My guess is to use the bInterfaceNumber attribute but when I put that in, nothing happens and it seems to completely bypass my rule.
Can anyone help me with this?
You can use ENV{ID_USB_INTERFACE_NUM}, defined in /lib64/udev/rules.d/60-persistent-serial.rules
Use udevadm test to check what environment available.