Re: Fixing the kernels backlight API

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