lpc: backlight control fails to enable for display v2

I am using a kernel based on linux-libre-arm64-mnt-reform@6.16.7 packaged in Guix and the unmodified version 1.79 of the reform2_lpc module built for that kernel.

The module works as expected, except that backlight control for MNT Pocket Reform with Display Version 2 is not enabled: dmesg-repro

When reloading the module after booting using rmmod/modprobe, the backlight control is enabled as expected.

I suspect this is a race condition where the module is loaded before the panel-mnt-pocket-reform driver is initialised so the mnt_pocket_reform_get_panel_version symbol is not available yet, causing the conditional enabling of backlight control to be skipped without even checking the version.

A possible workaround is to add a delay before checking the version: reform2-lpc-delay.patch dmesg-workaround