On Mon, Oct 24, 2016 at 04:08:47PM +0300, Marta Lofstedt wrote: > Hi David, > > I am currently investigating: > https://bugs.freedesktop.org/show_bug.cgi?id=96572 > > Martin Peres suggested that your patches: > https://lists.freedesktop.org/archives/dri-devel/2014-September/thread.html#67984 > could solve the xf86-video-modesetting backlight issues. > > I have rebased your patches and I am working on an IGT > test for the functionality. With my i915 implementation > and the small included bug-fix, I can update the drm BACKLIGHT > property and the value is updated in the backlight class device. > However, if I set the brigness value through the sysfs file of > the backlight class device the drm BRIGHTNESS property does not > update which would be confusing to users. > > My understanding is that DRM properties are cached and, by design, > do not have the capability to read the status from the driver. > > What do we want to do about this? Fix it I'd say. But right now there's no callback for drivers to return non-ATOMIC properties. Only old property values are cached like this. I guess we can add a get_property hook, which is optional, and which would fall back to the cached value if need. A bit a pain to wire up, but should get the job done. Maybe just start out with a callback for connectors only, instead of all kms objects which can have a property attached. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
