I recently got a ThinkPad X1 Extreme 2nd Generation for fixing some issues on, and noticed that out of the box the backlight doesn't work. Along the way of fixing that, I found a few issues with how i915 handles DPCD AUX backlight control and fixed them. Now I've got working backlight controls, hooray! Note that this patch series also enables DPCD aux backlight control by default based on what the VBT tells us. Lyude Paul (5): drm/i915: Fix eDP DPCD aux max backlight calculations drm/i915: Assume 100% brightness when not in DPCD control mode drm/i915: Fix DPCD register order in intel_dp_aux_enable_backlight() drm/i915: Auto detect DPCD backlight support by default drm/i915: Force DPCD backlight mode on X1 Extreme 2nd Gen 4K AMOLED panel drivers/gpu/drm/drm_dp_helper.c | 4 + .../drm/i915/display/intel_display_types.h | 3 + .../drm/i915/display/intel_dp_aux_backlight.c | 167 ++++++++++++------ drivers/gpu/drm/i915/i915_params.c | 2 +- drivers/gpu/drm/i915/i915_params.h | 2 +- include/drm/drm_dp_helper.h | 8 + 6 files changed, 134 insertions(+), 52 deletions(-) -- 2.21.0 _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel