drm/i915: Track pfit enable state separately from size

Detangle the additional state of whether or not the hw has the pfit
enabled from whether it has zero size. This allows us to cleanly
distinguish in the code when we expect the pfit to be enabled (for
Haswell pc8), and when the BIOS is confused and needs sanitizing.

Reported-by: shui yanwei <yangweix.shui@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=68251
Tested-by: shui yanwei <yangweix.shui@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 2489d0b..375e6a7 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2249,7 +2249,7 @@
 		I915_WRITE(PIPESRC(intel_crtc->pipe),
 			   ((crtc->mode.hdisplay - 1) << 16) |
 			   (crtc->mode.vdisplay - 1));
-		if (!intel_crtc->config.pch_pfit.size &&
+		if (!intel_crtc->config.pch_pfit.enabled &&
 		    (intel_pipe_has_type(crtc, INTEL_OUTPUT_LVDS) ||
 		     intel_pipe_has_type(crtc, INTEL_OUTPUT_EDP))) {
 			I915_WRITE(PF_CTL(intel_crtc->pipe), 0);
@@ -3203,7 +3203,7 @@
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	int pipe = crtc->pipe;
 
-	if (crtc->config.pch_pfit.size) {
+	if (crtc->config.pch_pfit.enabled) {
 		/* Force use of hard-coded filter coefficients
 		 * as some pre-programmed values are broken,
 		 * e.g. x201.
@@ -3428,7 +3428,7 @@
 
 	/* To avoid upsetting the power well on haswell only disable the pfit if
 	 * it's in use. The hw state code will make sure we get this right. */
-	if (crtc->config.pch_pfit.size) {
+	if (crtc->config.pch_pfit.enabled) {
 		I915_WRITE(PF_CTL(pipe), 0);
 		I915_WRITE(PF_WIN_POS(pipe), 0);
 		I915_WRITE(PF_WIN_SZ(pipe), 0);
@@ -5859,6 +5859,7 @@
 	tmp = I915_READ(PF_CTL(crtc->pipe));
 
 	if (tmp & PF_ENABLE) {
+		pipe_config->pch_pfit.enabled = true;
 		pipe_config->pch_pfit.pos = I915_READ(PF_WIN_POS(crtc->pipe));
 		pipe_config->pch_pfit.size = I915_READ(PF_WIN_SZ(crtc->pipe));
 
@@ -6236,7 +6237,7 @@
 		if (!crtc->base.enabled)
 			continue;
 
-		if (crtc->pipe != PIPE_A || crtc->config.pch_pfit.size ||
+		if (crtc->pipe != PIPE_A || crtc->config.pch_pfit.enabled ||
 		    crtc->config.cpu_transcoder != TRANSCODER_EDP)
 			enable = true;
 	}
@@ -8205,9 +8206,10 @@
 		      pipe_config->gmch_pfit.control,
 		      pipe_config->gmch_pfit.pgm_ratios,
 		      pipe_config->gmch_pfit.lvds_border_bits);
-	DRM_DEBUG_KMS("pch pfit: pos: 0x%08x, size: 0x%08x\n",
+	DRM_DEBUG_KMS("pch pfit: pos: 0x%08x, size: 0x%08x, %s\n",
 		      pipe_config->pch_pfit.pos,
-		      pipe_config->pch_pfit.size);
+		      pipe_config->pch_pfit.size,
+		      pipe_config->pch_pfit.enabled ? "enabled" : "disabled");
 	DRM_DEBUG_KMS("ips: %i\n", pipe_config->ips_enabled);
 }
 
@@ -8603,8 +8605,11 @@
 	if (INTEL_INFO(dev)->gen < 4)
 		PIPE_CONF_CHECK_I(gmch_pfit.pgm_ratios);
 	PIPE_CONF_CHECK_I(gmch_pfit.lvds_border_bits);
-	PIPE_CONF_CHECK_I(pch_pfit.pos);
-	PIPE_CONF_CHECK_I(pch_pfit.size);
+	PIPE_CONF_CHECK_I(pch_pfit.enabled);
+	if (current_config->pch_pfit.enabled) {
+		PIPE_CONF_CHECK_I(pch_pfit.pos);
+		PIPE_CONF_CHECK_I(pch_pfit.size);
+	}
 
 	PIPE_CONF_CHECK_I(ips_enabled);