Fixing the kernels backlight API

[Alexander E. Patrakov]

13.02.2014 04:26, David Herrmann wrote:
> The "attach" stuff actually sounds doable, but who decides which one
> to attach? You still need some user-space script during device-plug
> for that.
> But to be honest, the simplest way would be a "backlightd"
> bus-activatable daemon. SetBacklight() then takes a DRM-connector and
> brightness-value, which the daemon looks up in /sys and sets.. This
> has the advantage that we can do any fancy matching in user-space. We
> can provide quirks (maybe even via udev-hwdb) and other helpers for
> weird setups.

What would be done with Samsung monitors (like an old SyncMaster 770P) 
that have a DVI connection, no physical buttons and have to be 
controlled via DDC-CI? Currently, ddccontrol works (via /dev/i2c-*), but 
only from root. I would like this use case to be covered in such a way 
that it could work both in Xorg and in Wayland, and, if possible, 
without races related to i2c usage from the kernel and from userspace.

-- 
Alexander E. Patrakov