On Thu, 25 Jul 2019, Daniel Vetter <daniel@xxxxxxxx> wrote: > On Thu, Jul 25, 2019 at 03:35:40PM +0800, Kai-Heng Feng wrote: >> The next question is, how do we change the brightness level for OLED >> displays? Is changing gamma value a good way to do it? > > There's no overall amplifier knob to set general brightness on these? Usually there would be. There's no backlight, it's just the OLED brightness, so you'd need to talk to the panel itself. On eDP this would be accomplished by using DPCD, on command mode DSI by using DCS commands. VESA specifies the DPCD commands to use, and we have some level of support for that in i915 (granted, should be one level higher in drm core, but I digress). It's just that at least in the case of the referenced bug, it doesn't seem to use the standard DPCD commands. To support that, someone would have to acquire the panel specs or reverse engineer the proprietary stuff. And then you'd have to mess the driver to do things differently to cater for individual proprietary panels. BR, Jani. -- Jani Nikula, Intel Open Source Graphics Center _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
