Re: [PATCH 1/2] efi: Save Brightness using EFI on Macs

Lukas Wunner
2026-02-08T13:16:33Z

On Sun, Feb 08, 2026 at 11:45:55AM +0100, Hans de Goede wrote:
> I was already worried about the shutdown approach on v1,
> but did not say anything since I'm not that familiar
> with apple hw and other apple code is already doing
> something similar.

Yes, macOS saves the brightness so that it's persisted across reboots
and can be set already by the EFI firmware, avoiding a bloom effect
(brightness change) on handover to the OS. We want to provide the
same seamless user experience on Linux that users have grown accustomed
to on macOS, I think that's a reasonable thing to do.

> But writing a non-volatile EFI variable every 300ms is
> just a very very bad idea.

Agreed. But what do you think about a delayed write when brightness
is changed, so that brightness is persisted even if the OS crashes?
Users don't change brightness that often, I can't imagine that it
amounts to a significantly higher number of writes than if it's
only done on shutdown.

Thanks,

Lukas