[PATCH v2 04/10] drm/i915: Extract chv_color_check()

Ville Syrjala
2019-03-27T15:51:02Z

Since CHV has the CGM unit we require a custom implementation
of .color_check().

This fixes the computation of gamma_enable as previously we
left it enabled even when were using the CGM gamma instead.
Now we turn off the legacy LUT unless it's actually required.

v2: Add some comment explaining the color pipeline (Matt)

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
---
drivers/gpu/drm/i915/intel_color.c | 40 +++++++++++++++++++++++++++---
1 file changed, 36 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_color.c b/drivers/gpu/drm/i915/intel_color.c
index cdd5eccb767b..87cc204a1dbf 100644
--- a/drivers/gpu/drm/i915/intel_color.c
+++ b/drivers/gpu/drm/i915/intel_color.c
@@ -848,6 +848,41 @@ static u32 chv_cgm_mode(const struct intel_crtc_state *crtc_state)
return cgm_mode;
}

+/*
+ * CHV color pipeline:
+ * u0.10 -> CGM degamma -> u0.14 -> CGM csc -> u0.14 -> CGM gamma ->
+ * u0.10 -> WGC csc -> u0.10 -> pipe gamma -> u0.10
+ *
+ * We always bypass the WGC csc and use the CGM csc
+ * instead since it has degamma and better precision.
+ */
+static int chv_color_check(struct intel_crtc_state *crtc_state)
+{
+ int ret;
+
+ ret = check_luts(crtc_state);
+ if (ret)
+ return ret;
+
+ /*
+ * Pipe gamma will be used only for the legacy LUT.
+ * Otherwise we bypass it and use the CGM gamma instead.
+ */
+ crtc_state->gamma_enable =
+ crtc_state_is_legacy_gamma(crtc_state) &&
+ !crtc_state->c8_planes;
+
+ crtc_state->gamma_mode = GAMMA_MODE_MODE_8BIT;
+
+ crtc_state->cgm_mode = chv_cgm_mode(crtc_state);
+
+ ret = intel_color_add_affected_planes(crtc_state);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
static int _intel_color_check(struct intel_crtc_state *crtc_state)
{
struct drm_i915_private *dev_priv = to_i915(crtc_state->base.crtc->dev);
@@ -877,9 +912,6 @@ static int _intel_color_check(struct intel_crtc_state *crtc_state)

crtc_state->csc_mode = 0;

- if (IS_CHERRYVIEW(dev_priv))
- crtc_state->cgm_mode = chv_cgm_mode(crtc_state);
-
if (!crtc_state->gamma_enable ||
crtc_state_is_legacy_gamma(crtc_state))
crtc_state->gamma_mode = GAMMA_MODE_MODE_8BIT;
@@ -917,7 +949,7 @@ void intel_color_init(struct intel_crtc *crtc)

if (HAS_GMCH(dev_priv)) {
if (IS_CHERRYVIEW(dev_priv)) {
- dev_priv->display.color_check = _intel_color_check;
+ dev_priv->display.color_check = chv_color_check;
dev_priv->display.color_commit = i9xx_color_commit;
dev_priv->display.load_luts = cherryview_load_luts;
} else {