[Intel-gfx] [PATCH 4/5] drm/i915/icl: Skip init for an already enabled combo PHY

[Imre Deak]

Bspec says we should skip the initialization of combo PHYs that are
already initialized. We'll need to reinit the PHYs more frequently
when exiting from DC6 (after the next patch), so let's make sure the
uninit sequence complies with the spec. For safety skip the init only if
all the PHY register fields have their expected values.

Bspec: 21257
Cc: Paulo Zanoni <paulo.r.zanoni at intel.com>
Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Cc: José Roberto de Souza <jose.souza at intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
Signed-off-by: Imre Deak <imre.deak at intel.com>
---
 drivers/gpu/drm/i915/intel_combo_phy.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_combo_phy.c b/drivers/gpu/drm/i915/intel_combo_phy.c
index 1522e2a25390..7b911702f834 100644
--- a/drivers/gpu/drm/i915/intel_combo_phy.c
+++ b/drivers/gpu/drm/i915/intel_combo_phy.c
@@ -220,6 +220,12 @@ void icl_combo_phys_init(struct drm_i915_private *dev_priv)
 	for (port = PORT_A; port <= PORT_B; port++) {
 		u32 val;
 
+		if (icl_combo_phy_verify_state(dev_priv, port)) {
+			DRM_DEBUG_DRIVER("Port-%c combo PHY already enabled, won't reprogram it.\n",
+					 port_name(port));
+			continue;
+		}
+
 		val = I915_READ(ICL_PHY_MISC(port));
 		val &= ~ICL_PHY_MISC_DE_IO_COMP_PWR_DOWN;
 		I915_WRITE(ICL_PHY_MISC(port), val);
-- 
2.13.2