From 6f1e094fb6e98b99bda21133fea55970d82c2045 Mon Sep 17 00:00:00 2001 From: Chaitanya Kumar Borah Date: Wed, 3 Dec 2025 14:22:02 +0530 Subject: [PATCH] drm/i915/color: Preserve sign bit when int_bits is Zero When int_bits == 0, we lose the sign bit when we do the range check and apply the mask. Fix this by ensuring a minimum of one integer bit, which guarantees space for the sign bit in fully fractional representations (e.g. S0.12) Reviewed-by: Suraj Kandpal Signed-off-by: Chaitanya Kumar Borah Signed-off-by: Uma Shankar Link: https://patch.msgid.link/20251203085211.3663374-7-uma.shankar@intel.com Signed-off-by: Jani Nikula --- drivers/gpu/drm/i915/display/intel_color.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/gpu/drm/i915/display/intel_color.c b/drivers/gpu/drm/i915/display/intel_color.c index 33fe5c9b4663..81b87fed8878 100644 --- a/drivers/gpu/drm/i915/display/intel_color.c +++ b/drivers/gpu/drm/i915/display/intel_color.c @@ -613,6 +613,8 @@ static u16 ctm_to_twos_complement(u64 coeff, int int_bits, int frac_bits) if (CTM_COEFF_NEGATIVE(coeff)) c = -c; + int_bits = max(int_bits, 1); + c = clamp(c, -(s64)BIT(int_bits + frac_bits - 1), (s64)(BIT(int_bits + frac_bits - 1) - 1)); -- 2.47.3