From: Andres Calderon Jaramillo <andrescj@xxxxxxxxxxxx> commit 00f9a08fbc3c703b71842a5425c1eb82053c8a70 upstream. Prevent the ICL HDR plane pipeline from performing YUV color range correction twice when the input is in limited range. This is done by removing the limited-range code from icl_program_input_csc(). 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 Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Andres Calderon Jaramillo <andrescj@xxxxxxxxxxxx> Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> Link: https://patchwork.freedesktop.org/patch/msgid/20201215224219.3896256-1-andrescj@xxxxxxxxxx (cherry picked from commit fed387572040e84ead53852a7820e30a30e515d0) Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx> Link: https://patchwork.freedesktop.org/patch/msgid/20210202084553.30691-1-ville.syrjala@xxxxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/gpu/drm/i915/display/intel_display.c | 2 drivers/gpu/drm/i915/display/intel_sprite.c | 65 ++++----------------------- 2 files changed, 12 insertions(+), 55 deletions(-) --- a/drivers/gpu/drm/i915/display/intel_display.c +++ b/drivers/gpu/drm/i915/display/intel_display.c @@ -4880,6 +4880,8 @@ u32 glk_plane_color_ctl(const struct int plane_color_ctl |= PLANE_COLOR_YUV_RANGE_CORRECTION_DISABLE; } else if (fb->format->is_yuv) { plane_color_ctl |= PLANE_COLOR_INPUT_CSC_ENABLE; + if (plane_state->hw.color_range == DRM_COLOR_YCBCR_FULL_RANGE) + plane_color_ctl |= PLANE_COLOR_YUV_RANGE_CORRECTION_DISABLE; } return plane_color_ctl; --- a/drivers/gpu/drm/i915/display/intel_sprite.c +++ b/drivers/gpu/drm/i915/display/intel_sprite.c @@ -469,13 +469,19 @@ skl_program_scaler(struct intel_plane *p /* Preoffset values for YUV to RGB Conversion */ #define PREOFF_YUV_TO_RGB_HI 0x1800 -#define PREOFF_YUV_TO_RGB_ME 0x1F00 +#define PREOFF_YUV_TO_RGB_ME 0x0000 #define PREOFF_YUV_TO_RGB_LO 0x1800 #define ROFF(x) (((x) & 0xffff) << 16) #define GOFF(x) (((x) & 0xffff) << 0) #define BOFF(x) (((x) & 0xffff) << 16) +/* + * Programs the input color space conversion stage for ICL HDR planes. + * Note that it is assumed that this stage always happens after YUV + * range correction. Thus, the input to this stage is assumed to be + * in full-range YCbCr. + */ static void icl_program_input_csc(struct intel_plane *plane, const struct intel_crtc_state *crtc_state, @@ -523,52 +529,7 @@ icl_program_input_csc(struct intel_plane 0x0, 0x7800, 0x7F10, }, }; - - /* Matrix for Limited Range to Full Range Conversion */ - static const u16 input_csc_matrix_lr[][9] = { - /* - * BT.601 Limted range YCbCr -> full range RGB - * The matrix required is : - * [1.164384, 0.000, 1.596027, - * 1.164384, -0.39175, -0.812813, - * 1.164384, 2.017232, 0.0000] - */ - [DRM_COLOR_YCBCR_BT601] = { - 0x7CC8, 0x7950, 0x0, - 0x8D00, 0x7950, 0x9C88, - 0x0, 0x7950, 0x6810, - }, - /* - * BT.709 Limited range YCbCr -> full range RGB - * The matrix required is : - * [1.164384, 0.000, 1.792741, - * 1.164384, -0.213249, -0.532909, - * 1.164384, 2.112402, 0.0000] - */ - [DRM_COLOR_YCBCR_BT709] = { - 0x7E58, 0x7950, 0x0, - 0x8888, 0x7950, 0xADA8, - 0x0, 0x7950, 0x6870, - }, - /* - * BT.2020 Limited range YCbCr -> full range RGB - * The matrix required is : - * [1.164, 0.000, 1.678, - * 1.164, -0.1873, -0.6504, - * 1.164, 2.1417, 0.0000] - */ - [DRM_COLOR_YCBCR_BT2020] = { - 0x7D70, 0x7950, 0x0, - 0x8A68, 0x7950, 0xAC00, - 0x0, 0x7950, 0x6890, - }, - }; - const u16 *csc; - - if (plane_state->hw.color_range == DRM_COLOR_YCBCR_FULL_RANGE) - csc = input_csc_matrix[plane_state->hw.color_encoding]; - else - csc = input_csc_matrix_lr[plane_state->hw.color_encoding]; + const u16 *csc = input_csc_matrix[plane_state->hw.color_encoding]; intel_de_write_fw(dev_priv, PLANE_INPUT_CSC_COEFF(pipe, plane_id, 0), ROFF(csc[0]) | GOFF(csc[1])); @@ -585,14 +546,8 @@ icl_program_input_csc(struct intel_plane intel_de_write_fw(dev_priv, PLANE_INPUT_CSC_PREOFF(pipe, plane_id, 0), PREOFF_YUV_TO_RGB_HI); - if (plane_state->hw.color_range == DRM_COLOR_YCBCR_FULL_RANGE) - intel_de_write_fw(dev_priv, - PLANE_INPUT_CSC_PREOFF(pipe, plane_id, 1), - 0); - else - intel_de_write_fw(dev_priv, - PLANE_INPUT_CSC_PREOFF(pipe, plane_id, 1), - PREOFF_YUV_TO_RGB_ME); + intel_de_write_fw(dev_priv, PLANE_INPUT_CSC_PREOFF(pipe, plane_id, 1), + PREOFF_YUV_TO_RGB_ME); intel_de_write_fw(dev_priv, PLANE_INPUT_CSC_PREOFF(pipe, plane_id, 2), PREOFF_YUV_TO_RGB_LO); intel_de_write_fw(dev_priv,
