Raspberry Pi scanning issue

[madhephaestus]

Using the hid4java On windows, and x86_64 works well, but the same jar fails to open devices on a Raspberry Pi. Are there any special instructions or libraries that should be installed to make the Pi work the same as Ubuntu on x86?

Tested Non-working on Pi 3 Pi 4 2gb Pi 4 4gb Pi Zero

Jvm: https://chriswhocodes.com/downloads/openjfx-8u60-sdk-overlay-linux-armv6hf.zip

[gary-rowe]

Thanks for the testing - really appreciate the help.

The RPi support is a bit flaky at the moment. I'm having trouble cross-compiling the hidapi library to armv6. I'll keep at it and let you know here when the develop branch has an update.

[madhephaestus]

I will offer, as a bounty, a free SmallKat https://hackaday.io/project/164727-smallkat-an-adorable-dynamics-oriented-robot-cat kit to whomever solves this issue :)

[madhephaestus]

Upon further testing the HID device is found, and hid4java attempts to connect to it. The device receives no packets at all. The response times out after a minute. On timeout, device .disconnect is called, this causes a Fatal error:

#
# A fatal error has been detected by the Java Runtime Environment:
#
#  SIGSEGV (0xb) at pc=0x9e7e46e8, pid=1414, tid=0x9de91460
#
# JRE version: OpenJDK Runtime Environment (8.0_212-b01) (build 1.8.0_212-8u212-b01-1+rpi1-b01)
# Java VM: OpenJDK Client VM (25.212-b01 mixed mode linux-aarch32 )
# Problematic frame:
# C  [libusb-1.0.so.0+0x96e8]  libusb_get_next_timeout+0x60
#
# Core dump written. Default location: /home/pi/core or core.1414
#
# An error report file with more information is saved as:
# /home/pi/hs_err_pid1414.log
#
# If you would like to submit a bug report, please visit:
#   http://bugreport.java.com/bugreport/crash.jsp
#

I have attached the core-dump hs_err_pid1414.log

Another strange behaviour during this test is that the keyboard and mouse lock up as soon as the JVM loads the the hid4Java (from a groovy script at runtime). The kb and mouse are locked while the test program runs, then once the above error prints out, the kb and mouse come back.

[gary-rowe]

Thanks for the update. I'm still working on getting the RPi cross-compilation to work in the dockcross environment.

[gary-rowe]

I've pushed a new version of hid4java-develop-SNAPSHOT to Maven Central. it should contain a working RPi shared library now.

[madhephaestus]

YOU ROCK FOR DOING THIS SO FAST! One of my students is running through the tests tonight, ill report back in the morning :)

[gary-rowe]

There'll be another update coming along in a moment. I've found a bug with the RPi library.

Edit: Fresh version added to Maven Central snapshots.

[madhephaestus]

I cant seem to be able to load the snapshot. It isnt published here:

https://repo1.maven.org/maven2/org/hid4java/hid4java/

We are testing using the dep string:

implementation 'org.hid4java:hid4java:hid4java-develop-SNAPSHOT'

Can you tell me what dep string we should use to load this snapshot version? do i need to add a grab-resolver source?

[madhephaestus]

Found how to include it, were still getting an error. This is a New error, so i call this progress!

org.hid4java.HidException: Hidapi did not initialise: Unable to load library 'hidapi': Native library (linux-arm/libhidapi.so) not found in resource path ([file:/home/pi/.groovy/grapes/org.hid4java/hid4java/jars/hid4java-develop-SNAPSHOT.jar, file:/home/pi/.groovy/grapes/net.java.dev.jna/jna/jars/jna-4.1.0.jar, file:/home/pi/.groovy/grapes/com.neuronrobotics/SimplePacketComsJava-HID/jars/SimplePacketComsJava-HID-0.13.1.jar, file:/home/pi/.groovy/grapes/com.neuronrobotics/SimplePacketComsJava/jars/SimplePacketComsJava-0.10.1.jar])
    at org.hid4java.HidDeviceManager.<init>(HidDeviceManager.java:89)
    at org.hid4java.HidServices.<init>(HidServices.java:88)
    at org.hid4java.HidServices.<init>(HidServices.java:76)
    at org.hid4java.HidServices.<init>(HidServices.java:63)
    at org.hid4java.HidManager.getHidServices(HidManager.java:50)
    at edu.wpi.SimplePacketComs.phy.HIDSimplePacketComs.connectDeviceImp(HIDSimplePacketComs.java:66)

[OE4AMW]

Hi @madhephaestus, I experienced the same issue (Unable to load library 'hidapi': Native library (linux-arm/libhidapi.so) not found in resource path) when using https://raw.githubusercontent.com/bitcoin-solutions/mbhd-maven/master/snapshots/org/hid4java/hid4java/develop-SNAPSHOT/hid4java-develop-SNAPSHOT.jar (as described in README.md)

For some reason, the hidjava-develop-SNAPSHOT.jar does not contain a folder linux-arm with a libhidapi.so, instead there is only a libhidapipi.so in the root-folder. Manually "fixing" the jar (by renaming it to zip, changing the folder/filename, re-zipping and renaming back to .jar) helped in my case.

[gary-rowe]

I've updated the README in develop branch to include suitable Gradle configuration for the snapshot releases.

repositories {
    mavenCentral()
}

dependencies {
    implementation('org.hid4java:hid4java:develop-SNAPSHOT')
}

If this fixes your problems, please let me know.

[gary-rowe]

I should add that Maven Central has a new develop-SNAPSHOT that should fix your issue.

[gary-rowe]

I've verified that the latest build (using JNA 5.5.0) works on a RPi Model B Rev 2 which is linux-arm using hard float. This should sort out any issues with SIGILL (0x4) or SIGSEGV (0xb).

Closing.