[Intel-gfx] [PATCH 2/3] drm/i915/icl: apply Display WA #1178 to fix type C dongles

[Radhakrishna Sripada]

From: Lucas De Marchi <lucas.demarchi at intel.com>

Display WA #1178 is meant to fix Aux channel voltage swing too low with
some type C dongles. Although it is for type C, of ICL it only applies
to combo phy and not to eDP. This means we need to apply the WA only on
Aux B.

v2: simplify macro with w/a register (Paulo)
v3: Rebase on drm-tip. (Imre)

Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
Cc: Paulo Zanoni <paulo.r.zanoni at intel.com>
Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Signed-off-by: Lucas De Marchi <lucas.demarchi at intel.com>
---
 drivers/gpu/drm/i915/i915_reg.h         | 4 ++++
 drivers/gpu/drm/i915/intel_runtime_pm.c | 7 +++++++
 2 files changed, 11 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 82f246ad87a8..d61bfb305e93 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -8929,6 +8929,10 @@ enum skl_power_gate {
 #define   CNL_AUX_ANAOVRD1_ENABLE	(1 << 16)
 #define   CNL_AUX_ANAOVRD1_LDO_BYPASS	(1 << 23)
 
+#define ICL_AUX_ANAOVRD1_B		_MMIO(0x6C398)
+#define   ICL_AUX_ANAOVRD1_LDO_BYPASS	(1 << 7)
+#define   ICL_AUX_ANAOVRD1_ENABLE	(1 << 0)
+
 /* HDCP Key Registers */
 #define HDCP_KEY_CONF			_MMIO(0x66c00)
 #define  HDCP_AKSV_SEND_TRIGGER		BIT(31)
diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
index 0fdabce647ab..a97d2f762b77 100644
--- a/drivers/gpu/drm/i915/intel_runtime_pm.c
+++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
@@ -436,6 +436,13 @@ icl_combo_phy_aux_power_well_enable(struct drm_i915_private *dev_priv,
 	I915_WRITE(ICL_PORT_CL_DW12(port), val | ICL_LANE_ENABLE_AUX);
 
 	hsw_wait_for_power_well_enable(dev_priv, power_well);
+
+	/* Display WA #1178: icl */
+	if (IS_ICELAKE(dev_priv) && pw_idx == ICL_PW_CTL_IDX_AUX_B) {
+		val = I915_READ(ICL_AUX_ANAOVRD1_B);
+		val |= ICL_AUX_ANAOVRD1_ENABLE | ICL_AUX_ANAOVRD1_LDO_BYPASS;
+		I915_WRITE(ICL_AUX_ANAOVRD1_B, val);
+	}
 }
 
 static void
-- 
2.9.3