UART sensors broken in ev3dev-2.3.3 kernel

[dlech]

Describe the bug
After upgrading to 4.14.111-ev3dev-2.3.3-ev3 kernel, EV3 UART sensors are no longer detected.

To Reproduce
Steps to reproduce the behavior:

1. Upgrade kernel to 4.14.111-ev3dev-2.3.3-ev3
2. Reboot
3. Plug in a UART sensor
4. No sensor appears

Expected behavior
Sensor should work like previous versions

Robot (please complete the following information):

Image file:         ev3dev-stretch-ev3-generic-2018-06-13
Kernel version:     4.14.111-ev3dev-2.3.3-ev3
Brickman:           0.10.0
BogoMIPS:           148.88
Bluetooth:          2.1
Board:              board0
BOARD_INFO_HW_REV=7
BOARD_INFO_MODEL=LEGO MINDSTORMS EV3
BOARD_INFO_ROM_REV=6
BOARD_INFO_SERIAL_NUM=0016533F4838
BOARD_INFO_TYPE=main

Additional context

dmesg shows...

[    2.228164] lego-port port1: Added new device 'ev3-ports:in3:ev3-uart-host'
[   51.547561] Registered EV3 UART sensor line discipline. (29)

so we are getting part of the way there.

Also reported by CocoaGeek: on IRC.

[dlech]

Regression probably due to ev3dev/lego-linux-drivers@2ce65b0

[DJuego]

I think I have this problem! :-O

DJuego

[Chickenboy445]

How can I have my sensors working? Should I download an older version of the kernel? If so, which one should I pick?

[JorgePe]

ev3dev released with LEGO Education EV3 MicroPython seems to works fine:

Image file:         ev3-micropython-v1.0.0-sd-card-image
Kernel version:     4.14.96-ev3dev-2.3.2-ev3

the kernel is from Jan 27 so is recent

[dlech]

Try this:

sudo flash-kernel --force 4.14.96-ev3dev-2.3.2-ev3
sudo reboot

[Chickenboy445]

That worked! Thank you so much for your help. I have a pretty tough project to do with this and without sensors it would have been impossible. Thanks!

[sdebaerd]

I'm experiencing the same problem, but it's not resolved after flashing the older kernel (and rebooting).
The sensor page remains empty, also when trying to use the java lang, the jar crashes with the following stack:

Exception in thread "main" java.lang.RuntimeException: The path doesn't exist: /sys/class/lego-sensor
at ev3dev.utils.Sysfs.getElements(Sysfs.java:107)
at ev3dev.hardware.EV3DevDevice.detect(EV3DevDevice.java:57)
at ev3dev.hardware.EV3DevSensorDevice.(EV3DevSensorDevice.java:40)
at ev3dev.sensors.BaseSensor.(BaseSensor.java:22)
at ev3dev.sensors.ev3.EV3ColorSensor.(EV3ColorSensor.java:48)
at example.programming.SimpleWebServer.(SimpleWebServer.java:41)
at example.programming.SimpleWebServer.main(SimpleWebServer.java:166)

When using the "old" lejos image or standard mindstorms firmware, the sensor is recognized.

dmesg is though showing the correct details.

[ 1160.090079] lego-port port0: Added new device 'ev3-ports:in1:ev3-uart-host'