On Fri, Feb 23, 2018 at 11:26:41AM -0500, Harry Wentland wrote: > On 2018-02-22 04:42 PM, Ville Syrjala wrote: > > From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > > > > 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@xxxxxxxxxxxxxxxxxxxxx > > Cc: Mihail Atanassov <mihail.atanassov@xxxxxxx> > > Cc: Liviu Dudau <liviu.dudau@xxxxxxx> > > Cc: Brian Starkey <brian.starkey@xxxxxxx> > > Cc: Mali DP Maintainers <malidp@xxxxxxxxxxxx> > > Cc: Johnson Lin <johnson.lin@xxxxxxxxx> > > Cc: Uma Shankar <uma.shankar@xxxxxxxxx> > > Cc: Shashank Sharma <shashank.sharma@xxxxxxxxx> > > Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > > Good clarification. Our new CTM implementation (1) actually assumed > two's complement but nobody's using it yet, so we'll patch it to > convert. Another reason to start looking into igt and the tests there? That would have caught this too ... -Daniel > > Reviewed-by: Harry Wentland <harry.wentland@xxxxxxx> > > (1) https://patchwork.freedesktop.org/patch/204005/ > > Harry > > > --- > > 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 { > > > _______________________________________________ > dri-devel mailing list > dri-devel@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/dri-devel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
