diff --git a/drivers/gpu/drm/i915/intel_color.c b/drivers/gpu/drm/i915/intel_color.c index aa66e952a95d377eac1f659510853a61cba9fbf7..a383d993b8449a9fd2d22a6dfbb521f3929e7b30 100644 --- a/drivers/gpu/drm/i915/intel_color.c +++ b/drivers/gpu/drm/i915/intel_color.c @@ -84,26 +84,25 @@ static bool crtc_state_is_legacy_gamma(struct drm_crtc_state *state) /* * When using limited range, multiply the matrix given by userspace by - * the matrix that we would use for the limited range. We do the - * multiplication in U2.30 format. + * the matrix that we would use for the limited range. */ -static void ctm_mult_by_limited(uint64_t *result, int64_t *input) +static void ctm_mult_by_limited(u64 *result, const u64 *input) { int i; - for (i = 0; i < 9; i++) - result[i] = 0; + for (i = 0; i < 9; i++) { + u64 user_coeff = input[i]; + u32 limited_coeff = CTM_COEFF_LIMITED_RANGE; + u32 abs_coeff = clamp_val(CTM_COEFF_ABS(user_coeff), 0, + CTM_COEFF_4_0 - 1) >> 2; - for (i = 0; i < 3; i++) { - int64_t user_coeff = input[i * 3 + i]; - uint64_t limited_coeff = CTM_COEFF_LIMITED_RANGE >> 2; - uint64_t abs_coeff = clamp_val(CTM_COEFF_ABS(user_coeff), - 0, - CTM_COEFF_4_0 - 1) >> 2; - - result[i * 3 + i] = (limited_coeff * abs_coeff) >> 27; - if (CTM_COEFF_NEGATIVE(user_coeff)) - result[i * 3 + i] |= CTM_COEFF_SIGN; + /* + * By scaling every co-efficient with limited range (16-235) + * vs full range (0-255) the final o/p will be scaled down to + * fit in the limited range supported by the panel. + */ + result[i] = mul_u32_u32(limited_coeff, abs_coeff) >> 30; + result[i] |= user_coeff & CTM_COEFF_SIGN; } }