drm/i915/icl: Work around broken VBTs for port F detection

VBT may include incorrect information about the presence of port F. Work
around this on SKUs where we know the port is not present.

v2:
- Fix IS_ICL_WITH_PORT_F, so it's useable from any context.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=108915
Cc: Mika Kahola <mika.kahola@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181220155211.31456-1-imre.deak@intel.com

drivers/gpu/drm/i915/i915_drv.h

@@ -2353,6 +2353,8 @@ static inline unsigned int i915_sg_segment_size(void)
 				 INTEL_INFO(dev_priv)->gt == 3)
 #define IS_CNL_WITH_PORT_F(dev_priv)   (IS_CANNONLAKE(dev_priv) && \
 					(INTEL_DEVID(dev_priv) & 0x0004) == 0x0004)
+#define IS_ICL_WITH_PORT_F(dev_priv)   (IS_ICELAKE(dev_priv) && \
+					INTEL_DEVID(dev_priv) != 0x8A51)
 
 #define IS_ALPHA_SUPPORT(intel_info) ((intel_info)->is_alpha_support)
 

drivers/gpu/drm/i915/intel_display.c

@@ -14376,8 +14376,10 @@ static void intel_setup_outputs(struct drm_i915_private *dev_priv)
 		/*
 		 * On some ICL SKUs port F is not present. No strap bits for
 		 * this, so rely on VBT.
+		 * Work around broken VBTs on SKUs known to have no port F.
 		 */
-		if (intel_bios_is_port_present(dev_priv, PORT_F))
+		if (IS_ICL_WITH_PORT_F(dev_priv) &&
+		    intel_bios_is_port_present(dev_priv, PORT_F))
 			intel_ddi_init(dev_priv, PORT_F);
 
 		icl_dsi_init(dev_priv);