CABC stands for the Content Adaptive Backlight Control. In the normal display the backlight which we see is due to the backlight which is being modulated by the filter, which is inturn dependent on the image. In brief the CABC does the histogram analysis of the image and then controls the filter and backlight. For example in CABC to display the dark image the backlight is dimmed and then controlls the filter to allow more light, because of which is power consuption will be reduced.
Below are the initial set of patches which supports the CABC. A field exits in the mipi configuration of the VBT which when enabled indiactes the CABC is supported. Depending on this filed the backlight control function pointer are initialized in the intel_panel.c file.
In case of dual link panels depending on the panel the DCS commands have to be send to either PORT A, PORT C or both PORT A and PORT C. Again a filed is added in the VBT to get this data from the version 197 onwards. One of the below patches parses these fields from the VBT.
Addressed the review comments of Jani, which were mentioned in the below https://lists.freedesktop.org/archives/intel-gfx/2015-November/081233.html
Cc: Jani Nikula jani.nikula@intel.com Cc: Daniel Vetter daniel.vetter@intel.com Cc: Yetunde Adebisi yetundex.adebisi@intel.com
Deepak M (2): drm/i915: Parsing the PWM cntrl and CABC ON/OFF fileds in VBT drm/i915: CABC support for backlight control
drivers/gpu/drm/i915/Makefile | 1 + drivers/gpu/drm/i915/i915_drv.h | 2 +- drivers/gpu/drm/i915/intel_bios.c | 10 ++ drivers/gpu/drm/i915/intel_bios.h | 5 +- drivers/gpu/drm/i915/intel_dsi.c | 17 +++- drivers/gpu/drm/i915/intel_dsi.h | 13 +++ drivers/gpu/drm/i915/intel_dsi_cabc.c | 179 ++++++++++++++++++++++++++++++++++ drivers/gpu/drm/i915/intel_panel.c | 4 + 8 files changed, 228 insertions(+), 3 deletions(-) create mode 100644 drivers/gpu/drm/i915/intel_dsi_cabc.c