drm/i915: Fix fastset vs. pfit on/off on HSW EDP transcoder

On HSW the pipe A panel fitter lives inside the display power well,
and the input MUX for the EDP transcoder needs to be configured
appropriately to route the data through the power well as needed.
Changing the MUX setting is not allowed while the pipe is active,
so we need to force a full modeset whenever we need to change it.

Currently we may end up doing a fastset which won't change the
MUX settings, but it will drop the power well reference, and that
kills the pipe.

Cc: stable@vger.kernel.org
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Fixes: d19f958d ("drm/i915: Enable fastset for non-boot modesets.")
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190425162906.5242-1-ville.syrjala@linux.intel.comReviewed-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>

drivers/gpu/drm/i915/intel_display.c

@@ -11937,6 +11937,7 @@ intel_pipe_config_compare(struct drm_i915_private *dev_priv,
 			  struct intel_crtc_state *pipe_config,
 			  bool adjust)
 {
+	struct intel_crtc *crtc = to_intel_crtc(current_config->base.crtc);
 	bool ret = true;
 	bool fixup_inherited = adjust &&
 		(current_config->base.mode.private_flags & I915_MODE_FLAG_INHERITED) &&
@@ -12158,6 +12159,14 @@ intel_pipe_config_compare(struct drm_i915_private *dev_priv,
 		PIPE_CONF_CHECK_X(gmch_pfit.pgm_ratios);
 	PIPE_CONF_CHECK_X(gmch_pfit.lvds_border_bits);
 
+	/*
+	 * Changing the EDP transcoder input mux
+	 * (A_ONOFF vs. A_ON) requires a full modeset.
+	 */
+	if (IS_HASWELL(dev_priv) && crtc->pipe == PIPE_A &&
+	    current_config->cpu_transcoder == TRANSCODER_EDP)
+		PIPE_CONF_CHECK_BOOL(pch_pfit.enabled);
+
 	if (!adjust) {
 		PIPE_CONF_CHECK_I(pipe_src_w);
 		PIPE_CONF_CHECK_I(pipe_src_h);

drivers/gpu/drm/i915/intel_pipe_crc.c

@@ -312,10 +312,17 @@ intel_crtc_crc_setup_workarounds(struct intel_crtc *crtc, bool enable)
 	pipe_config->base.mode_changed = pipe_config->has_psr;
 	pipe_config->crc_enabled = enable;
 
-	if (IS_HASWELL(dev_priv) && crtc->pipe == PIPE_A) {
+	if (IS_HASWELL(dev_priv) &&
+	    pipe_config->base.active && crtc->pipe == PIPE_A &&
+	    pipe_config->cpu_transcoder == TRANSCODER_EDP) {
+		bool old_need_power_well = pipe_config->pch_pfit.enabled ||
+			pipe_config->pch_pfit.force_thru;
+		bool new_need_power_well = pipe_config->pch_pfit.enabled ||
+			enable;
+
 		pipe_config->pch_pfit.force_thru = enable;
-		if (pipe_config->cpu_transcoder == TRANSCODER_EDP &&
-		    pipe_config->pch_pfit.enabled != enable)
+
+		if (old_need_power_well != new_need_power_well)
 			pipe_config->base.connectors_changed = true;
 	}