drm/i915: Fix legacy gamma mode for ICL

We must remember to actually enable the post CSC gamma if
we expect the legacy LUT to work. Seems to fix NV12 crc
tests on the SDR planes. Curiously we apparently managed to
get 100% match for the HDR planes even without chopping
off the low bits.

Cc: Uma Shankar <uma.shankar@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190315195445.26527-1-ville.syrjala@linux.intel.com
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>

diff --git a/drivers/gpu/drm/i915/intel_color.c b/drivers/gpu/drm/i915/intel_color.c
index 8038f0fc35ffb847059f12d50f9db98690c08ca9..467fd1a1630c200115324cd2572a35f3b7ae0667 100644 (file)
--- a/drivers/gpu/drm/i915/intel_color.c
+++ b/drivers/gpu/drm/i915/intel_color.c
@@ -832,6 +832,9 @@ int intel_color_check(struct intel_crtc_state *crtc_state)
        if (!crtc_state->gamma_enable ||
            crtc_state_is_legacy_gamma(crtc_state)) {
                crtc_state->gamma_mode = GAMMA_MODE_MODE_8BIT;
+               if (INTEL_GEN(dev_priv) >= 11 &&
+                   crtc_state->gamma_enable)
+                       crtc_state->gamma_mode |= POST_CSC_GAMMA_ENABLE;
                return 0;
        }