Meeting (BOF) at Plumbers Dublin to discuss backlight brightness as connector object property RFC?

Ville Syrjälä ville.syrjala at
Fri Sep 9 12:05:15 UTC 2022

On Fri, Sep 09, 2022 at 12:23:53PM +0200, Hans de Goede wrote:
> Hi All,
> I will be at Plumbers Dublin next week and I was wondering if
> anyone interested in this wants to get together for a quick
> discussion / birds of a feather session about this?
> I have just posted version 2 of the RFC:
> If you are interested in meeting up please send me
> an email off-list (no need to spam the list further with this)
> also please let me know if there are any times which do not
> work for you, and/or times which have your preference.
> I don't have a specific room/time for this yet, but if people
> are interested I will try to get a room from the organization
> and if that does not work out I'm sure we will figure something
> out.
> One of the things which I would like to discuss is using
> the backlight brightness as connector object property vs
> external (not part of the compositor) tools to control the
> brightness like e.g. xbacklight, quoting from the RFC:
> "people using
> non fully integrated desktop environments like e.g. sway often use custom
> scripts binded to hotkeys to get functionality like the brightness
> up/down keyboard hotkeys changing the brightness. This typically involves
> e.g. the xbacklight utility.
> Even if the xbacklight utility is ported to use kms with the new connector
> object brightness properties then this still will not work because
> changing the properties will require drm-master rights and e.g. sway will
> already hold those."
> Note one obvious solution here would be for these use-cases to keep
> using the old /sys/class/backlight interface for this, with the downside
> that we will then be stuck to that interface for ever...

Isn't xbacklight the thing that only works when you *have* the
backlight property? Ie. currently only works on intel ddx which
adds a custom property but doesn't work on modesetting ddx for

Ville Syrjälä

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