drm/i915: Fix pipe CSC post offset calculation

We were miscalculating the pipe CSC post offset for the full->limited
range conversion. The resulting post offset was double what it was
supposed to be, which caused blacks to come out grey when using
limited range output on HSW+.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=71769
Cc: stable@vger.kernel.org
Tested-by: Lauri Mylläri <lauri.myllari@gmail.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 0d9369578fde..898bd98c96ae 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -5815,7 +5815,7 @@ static void intel_set_pipe_csc(struct drm_crtc *crtc)
                 uint16_t postoff = 0;
 
                 if (intel_crtc->config.limited_color_range)
-                        postoff = (16 * (1 << 13) / 255) & 0x1fff;
+                        postoff = (16 * (1 << 12) / 255) & 0x1fff;
 
                 I915_WRITE(PIPE_CSC_POSTOFF_HI(pipe), postoff);
                 I915_WRITE(PIPE_CSC_POSTOFF_ME(pipe), postoff);