From deac453244d309ad7a94d0501eb5e0f9d8d1f1df Mon Sep 17 00:00:00 2001 From: Ville Syrjälä Date: Fri, 13 Oct 2023 16:14:02 +0300 Subject: drm/i915: Fix glk+ degamma LUT conversions MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The current implementation of change_lut_val_precision() is just a convoluted way of shifting by 8. Implement the proper rounding by just using drm_color_lut_extract() and intel_color_lut_pack() like everyone else does. And as the uapi can't handle >=1.0 values but the hardware can we need to clamp the results appropriately in the readout path. Signed-off-by: Ville Syrjälä Link: https://patchwork.freedesktop.org/patch/msgid/20231013131402.24072-5-ville.syrjala@linux.intel.com Reviewed-by: Chaitanya Kumar Borah Reviewed-by: Jani Nikula --- drivers/gpu/drm/i915/display/intel_color.c | 54 ++++++++++++++++-------------- 1 file changed, 28 insertions(+), 26 deletions(-) diff --git a/drivers/gpu/drm/i915/display/intel_color.c b/drivers/gpu/drm/i915/display/intel_color.c index 91f92844e213..c5092b7e87d5 100644 --- a/drivers/gpu/drm/i915/display/intel_color.c +++ b/drivers/gpu/drm/i915/display/intel_color.c @@ -1526,14 +1526,27 @@ static int glk_degamma_lut_size(struct drm_i915_private *i915) return 35; } -/* - * change_lut_val_precision: helper function to upscale or downscale lut values. - * Parameters 'to' and 'from' needs to be less than 32. This should be sufficient - * as currently there are no lut values exceeding 32 bit. - */ -static u32 change_lut_val_precision(u32 lut_val, int to, int from) +static u32 glk_degamma_lut(const struct drm_color_lut *color) +{ + return color->green; +} + +static void glk_degamma_lut_pack(struct drm_color_lut *entry, u32 val) +{ + /* PRE_CSC_GAMC_DATA is 3.16, clamp to 0.16 */ + entry->red = entry->green = entry->blue = min(val, 0xffffu); +} + +static u32 mtl_degamma_lut(const struct drm_color_lut *color) +{ + return drm_color_lut_extract(color->green, 24); +} + +static void mtl_degamma_lut_pack(struct drm_color_lut *entry, u32 val) { - return mul_u32_u32(lut_val, (1 << to)) / (1 << from); + /* PRE_CSC_GAMC_DATA is 3.24, clamp to 0.16 */ + entry->red = entry->green = entry->blue = + intel_color_lut_pack(min(val, 0xffffffu), 24); } static void glk_load_degamma_lut(const struct intel_crtc_state *crtc_state, @@ -1570,20 +1583,16 @@ static void glk_load_degamma_lut(const struct intel_crtc_state *crtc_state, * ToDo: Extend to max 7.0. Enable 32 bit input value * as compared to just 16 to achieve this. */ - u32 lut_val; - - if (DISPLAY_VER(i915) >= 14) - lut_val = change_lut_val_precision(lut[i].green, 24, 16); - else - lut_val = lut[i].green; - ilk_lut_write(crtc_state, PRE_CSC_GAMC_DATA(pipe), - lut_val); + DISPLAY_VER(i915) >= 14 ? + mtl_degamma_lut(&lut[i]) : glk_degamma_lut(&lut[i])); } /* Clamp values > 1.0. */ while (i++ < glk_degamma_lut_size(i915)) - ilk_lut_write(crtc_state, PRE_CSC_GAMC_DATA(pipe), 1 << 16); + ilk_lut_write(crtc_state, PRE_CSC_GAMC_DATA(pipe), + DISPLAY_VER(i915) >= 14 ? + 1 << 24 : 1 << 16); ilk_lut_write(crtc_state, PRE_CSC_GAMC_INDEX(pipe), 0); } @@ -3570,17 +3579,10 @@ static struct drm_property_blob *glk_read_degamma_lut(struct intel_crtc *crtc) for (i = 0; i < lut_size; i++) { u32 val = intel_de_read_fw(dev_priv, PRE_CSC_GAMC_DATA(pipe)); - /* - * For MTL and beyond, convert back the 24 bit lut values - * read from HW to 16 bit values to maintain parity with - * userspace values - */ if (DISPLAY_VER(dev_priv) >= 14) - val = change_lut_val_precision(val, 16, 24); - - lut[i].red = val; - lut[i].green = val; - lut[i].blue = val; + mtl_degamma_lut_pack(&lut[i], val); + else + glk_degamma_lut_pack(&lut[i], val); } intel_de_write_fw(dev_priv, PRE_CSC_GAMC_INDEX(pipe), -- cgit v1.2.3