From: Andres Calderon Jaramillo <andrescj@xxxxxxxxxxxx> Prevent the ICL HDR plane pipeline from performing YUV color range correction twice when the input is in limited range. Before this patch the following could happen: user space gives us a YUV buffer in limited range; per the pipeline in [1], the plane would first go through a "YUV Range correct" stage that expands the range; the plane would then go through the "Input CSC" stage which would also expand the range because icl_program_input_csc() would use a matrix and an offset that assume limited-range input; this would ultimately cause dark and light colors to appear darker and lighter than they should respectively. This is an issue because if a buffer switches between being scanned out and being composited with the GPU, the user will see a color difference. If this switching happens quickly and frequently, the user will perceive this as a flickering. [1] https://01.org/sites/default/files/documentation/intel-gfx-prm-osrc-icllp-vol12-displayengine_0.pdf#page=281 Signed-off-by: Andres Calderon Jaramillo <andrescj@xxxxxxxxxxxx> --- drivers/gpu/drm/i915/display/intel_display.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c index 761be8deaa9b..aeea344b06ad 100644 --- a/drivers/gpu/drm/i915/display/intel_display.c +++ b/drivers/gpu/drm/i915/display/intel_display.c @@ -4811,6 +4811,13 @@ u32 glk_plane_color_ctl(const struct intel_crtc_state *crtc_state, plane_color_ctl |= PLANE_COLOR_YUV_RANGE_CORRECTION_DISABLE; } else if (fb->format->is_yuv) { plane_color_ctl |= PLANE_COLOR_INPUT_CSC_ENABLE; + + /* + * Disable the YUV range correction stage because the input CSC + * stage already takes care of range conversion by using separate + * matrices and offsets depending on the color range. + */ + plane_color_ctl |= PLANE_COLOR_YUV_RANGE_CORRECTION_DISABLE; } return plane_color_ctl; -- 2.29.2.684.gfbc64c5ab5-goog _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
