Kernel BUG when loading classmate_laptop, accelerometer does not work

[Leonardo Soares Müller]

When trying to load the classmate_laptop module to enable the accelerometer, a kernel BUG is happening and the accelerometer isn't loaded. This problem was observed more often when reloading the classmate_laptop module after the boot.

However, this was observed on boot too. If this bug happens on boot, then the keyboard and touchpad may not work, making the netbook unusable until forcefully powered off.

This accelerometer can be found on, at least, the Positivo Mobo 5900 and Multilaser MLX5 Educ netbook models. On the Mobo, the accelerometer rarely causes problems (this netbook can be used as a tablet), but on the MLX5 the problems are frequent, requiring to reboot them two or even three times until the netbook's keyboard, touchpad and accelerometer work correctly.

While one possible approach would be to blacklist the classmate_laptop module, losing the access to the accelerometer would be a significant problem, at least on the Mobo 5900.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: linux-image-5.3.0-40-generic 5.3.0-40.32~18.04.1
ProcVersionSignature: Ubuntu 5.3.0-40.32~18.04.1-generic 5.3.18
Uname: Linux 5.3.0-40-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.11
Architecture: amd64
CurrentDesktop: XFCE
Date: Wed Mar 11 14:32:12 2020
InstallationDate: Installed on 2019-11-16 (116 days ago)
InstallationMedia: Xubuntu 18.04.3 LTS "Bionic Beaver" - Release amd64 (20190805)
SourcePackage: linux-signed-hwe
UpgradeStatus: No upgrade log present (probably fresh install)