On 8/24/21 5:47 PM, Barnabás Pőcze wrote:
Have you looked at `devm_backlight_device_register()`?
So regarding this suggestion, I have switched to devm_backlight_device_register(), but now I can't unload the module; it fails with EBUSY. I tried unbinding the device (via /sys/class/backlight/wmaa_backlight/device/driver/unbind), but that fails with ENODEV, maybe due to missing plumbing in wmi?
I'm not sure if it's expected for users to be able to unload their backlight drivers; on the random selection of notebooks that I have immediately available to me at the moment, the backlight driver is registered by the GPU driver, and that tends to be not unloadable because e.g. it's driving the console.
It's probably best to use devm_backlight_device_register() anyway since it seems the ordinary backlight_device_register() is deprecated, but I wanted to see if there were any strong opinions about whether it would be a problem that the driver can't be unloaded.
