Ubuntu 22.04: hibernate doesn't resume keyboard backlight status

I’ve been trying to get hibernate (suspend to disc) working with my FW16. Adding a swap partition, enabling said partition in grub and some more steps from the ubuntu help sites resulted in working hibernate and resume, but the keyboard and numpad backlights are also switched off yet don’t come back on again.

Is there a way to remedy this?

I believe that the keyboard back light is not something that is done in software. The EC tool might be able to allow you to set the backlight via the cli, but you would need a script to run before suspending / hibernating, so that a value could be checked when resuming.

Ultimately I think it probably makes sense to have the keyboard default to backlight off, as presumably setting and time of day will be different when you resume again.

Now my knowledge of the backlight functionality is based on the FW 13. The 16 uses a different keyboard and could function differently as well.

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If I shut down normally, the backlight comes on automatically. It’s on in BIOS, flickers off and on a couple times but ultimately stays on. I’ve got it at 100% all the time and most of the time need it for logging in. If anything, it should default to on or automatic depending on brightness sensor. But the latter would have to be implemented in EC I guess.

If I recall, in the 16 it’s a combination of the EC and the QMK firmware in the keyboard turning off the blacklight for sleep. Input modules have a SLEEP pin that current EC firmware uses to turn off lighting during sleep, though there has been some talk about using it to send lid closed status. [RESPONDED] Waking from suspend w/ lid closed - #13 by Kieran_Levin
So for this, the backlight not coming back on after sleep, the fault could be with the EC failing to turn off the sleep pin or QMK not responding to it, if it’s even programmed to come back automatically, I don’t know.

Do they respond to the hot key to turn them on, or are they stuck off?

This is not sleep, but hibernate.

The backlights do respond to the hot keys, both keyboard and numpad.

Sorry, I meant keyboard sleep, not PC sleep. When going into hibernate, the EC might use the sleep function via the input module’s SLEEP pin. The reason being, if AC power is still connected while hibernated, the USB ports may remain powered, potentially including the upper input modules, which are also USB.

Is there a solution yet? It’s the same with windows, after hibernate, the backlights won’t come back on, regardless of being attached to external power or not.