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>
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 0d93695..898bd98 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -5815,7 +5815,7 @@
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);