DRM_FIXED_ONE
s64 tolerance = div64_s64(DRM_FIXED_ONE, 1000000);
s64 sum = DRM_FIXED_ONE, term, y = x;
sum = drm_fixp_div(DRM_FIXED_ONE, sum);
#define DRM_FIXED_DECIMAL_MASK (DRM_FIXED_ONE - 1)
#define DRM_FIXED_ALMOST_ONE (DRM_FIXED_ONE - DRM_FIXED_EPSILON)