drm/i915/xelpd: Enable Pipe Degamma

BugLink: https://bugs.launchpad.net/bugs/1967274
Enable Pipe Degamma for XE_LPD. Extend the legacy implementation
to incorparate the extended lut size for XE_LPD.

v2: Added a helper for degamma lut size (Ville)

Signed-off-by: Uma Shankar <uma.shankar@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211207071135.3660332-3-uma.shankar@intel.com
(cherry picked from commit 17815f624a90579aeac4b700f8434e9ff6a6d001)
Signed-off-by: Chia-Lin Kao (AceLan) <acelan.kao@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

diff --git a/drivers/gpu/drm/i915/display/intel_color.c b/drivers/gpu/drm/i915/display/intel_color.c
index c095bd03a9af3d95b3c0331d10aa9923d6458606..c4a0b5ebf4cc7d24516668698ddc9b58af33942f 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_color.c
+++ b/drivers/gpu/drm/i915/display/intel_color.c
@@ -806,6 +806,14 @@ static void bdw_load_luts(const struct intel_crtc_state *crtc_state)
        }
 }
 
+static int glk_degamma_lut_size(struct drm_i915_private *i915)
+{
+       if (DISPLAY_VER(i915) >= 13)
+               return 131;
+       else
+               return 35;
+}
+
 static void glk_load_degamma_lut(const struct intel_crtc_state *crtc_state)
 {
        struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
@@ -825,8 +833,8 @@ static void glk_load_degamma_lut(const struct intel_crtc_state *crtc_state)
 
        for (i = 0; i < lut_size; i++) {
                /*
-                * First 33 entries represent range from 0 to 1.0
-                * 34th and 35th entry will represent extended range
+                * First lut_size entries represent range from 0 to 1.0
+                * 3 additional lut entries will represent extended range
                 * inputs 3.0 and 7.0 respectively, currently clamped
                 * at 1.0. Since the precision is 16bit, the user
                 * value can be directly filled to register.
@@ -842,7 +850,7 @@ static void glk_load_degamma_lut(const struct intel_crtc_state *crtc_state)
        }
 
        /* Clamp values > 1.0. */
-       while (i++ < 35)
+       while (i++ < glk_degamma_lut_size(dev_priv))
                intel_de_write_fw(dev_priv, PRE_CSC_GAMC_DATA(pipe), 1 << 16);
 
        intel_de_write_fw(dev_priv, PRE_CSC_GAMC_INDEX(pipe), 0);