VSYNC_POSITIVE
BIT(VSYNC_POSITIVE) : 0;
polflags |= BIT(VSYNC_POSITIVE);
val |= (flags & DRM_MODE_FLAG_NVSYNC) ? BIT(VSYNC_POSITIVE) : 0;
if (VSYNC_POSITIVE)
(VSYNC_POSITIVE) ? "+" : "-");
if (VSYNC_POSITIVE)