[PATCH 1/4] drm/uapi: The ctm matrix uses sign-magnitude representation

[Ville Syrjala]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

The documentation for the ctm matrix suggests a two's complement
format, but at least the i915 implementation is using sign-magnitude
instead. And looks like malidp is doing the same. Change the docs
to match the current implementation, and change the type from __s64
to __u64 to drive the point home.

Cc: dri-devel at lists.freedesktop.org
Cc: Mihail Atanassov <mihail.atanassov at arm.com>
Cc: Liviu Dudau <liviu.dudau at arm.com>
Cc: Brian Starkey <brian.starkey at arm.com>
Cc: Mali DP Maintainers <malidp at foss.arm.com>
Cc: Johnson Lin <johnson.lin at intel.com>
Cc: Uma Shankar <uma.shankar at intel.com>
Cc: Shashank Sharma <shashank.sharma at intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 include/uapi/drm/drm_mode.h | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
index 2c575794fb52..b5d7d9e0eff5 100644
--- a/include/uapi/drm/drm_mode.h
+++ b/include/uapi/drm/drm_mode.h
@@ -598,8 +598,11 @@ struct drm_mode_crtc_lut {
 };
 
 struct drm_color_ctm {
-	/* Conversion matrix in S31.32 format. */
-	__s64 matrix[9];
+	/*
+	 * Conversion matrix in S31.32 sign-magnitude
+	 * (not two's complement!) format.
+	 */
+	__u64 matrix[9];
 };
 
 struct drm_color_lut {
-- 
2.16.1