drm/i915: Clear pfit registers when not used by any outputs

... otherwise the panel-fitter may be left enabled with random settings
and cause unintended filtering (i.e. blurring of native modes on external
panels).

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=31942
Reported-and-tested-by: Ben Kohler <bkohler@gmail.com>
Tested-by: Ciprian Docan <docan@eden.rutgers.edu>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index bee24b1..255b52e 100644 (file)
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -5336,9 +5336,14 @@ static void intel_setup_outputs(struct drm_device *dev)
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct intel_encoder *encoder;
        bool dpd_is_edp = false;
+       bool has_lvds = false;
 
        if (IS_MOBILE(dev) && !IS_I830(dev))
-               intel_lvds_init(dev);
+               has_lvds = intel_lvds_init(dev);
+       if (!has_lvds && !HAS_PCH_SPLIT(dev)) {
+               /* disable the panel fitter on everything but LVDS */
+               I915_WRITE(PFIT_CONTROL, 0);
+       }
 
        if (HAS_PCH_SPLIT(dev)) {
                dpd_is_edp = intel_dpd_is_edp(dev);

diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 21551fe..e52c612 100644 (file)
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -237,7 +237,7 @@ extern bool intel_sdvo_init(struct drm_device *dev, int output_device);
 extern void intel_dvo_init(struct drm_device *dev);
 extern void intel_tv_init(struct drm_device *dev);
 extern void intel_mark_busy(struct drm_device *dev, struct drm_gem_object *obj);
-extern void intel_lvds_init(struct drm_device *dev);
+extern bool intel_lvds_init(struct drm_device *dev);
 extern void intel_dp_init(struct drm_device *dev, int dp_reg);
 void
 intel_dp_set_m_n(struct drm_crtc *crtc, struct drm_display_mode *mode,

diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
index 4324a32..f79327f 100644 (file)
--- a/drivers/gpu/drm/i915/intel_lvds.c
+++ b/drivers/gpu/drm/i915/intel_lvds.c
@@ -837,7 +837,7 @@ static bool intel_lvds_ddc_probe(struct drm_device *dev, u8 pin)
  * Create the connector, register the LVDS DDC bus, and try to figure out what
  * modes we can display on the LVDS panel (if present).
  */
-void intel_lvds_init(struct drm_device *dev)
+bool intel_lvds_init(struct drm_device *dev)
 {
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct intel_lvds *intel_lvds;
@@ -853,37 +853,37 @@ void intel_lvds_init(struct drm_device *dev)
 
        /* Skip init on machines we know falsely report LVDS */
        if (dmi_check_system(intel_no_lvds))
-               return;
+               return false;
 
        pin = GMBUS_PORT_PANEL;
        if (!lvds_is_present_in_vbt(dev, &pin)) {
                DRM_DEBUG_KMS("LVDS is not present in VBT\n");
-               return;
+               return false;
        }
 
        if (HAS_PCH_SPLIT(dev)) {
                if ((I915_READ(PCH_LVDS) & LVDS_DETECTED) == 0)
-                       return;
+                       return false;
                if (dev_priv->edp.support) {
                        DRM_DEBUG_KMS("disable LVDS for eDP support\n");
-                       return;
+                       return false;
                }
        }
 
        if (!intel_lvds_ddc_probe(dev, pin)) {
                DRM_DEBUG_KMS("LVDS did not respond to DDC probe\n");
-               return;
+               return false;
        }
 
        intel_lvds = kzalloc(sizeof(struct intel_lvds), GFP_KERNEL);
        if (!intel_lvds) {
-               return;
+               return false;
        }
 
        intel_connector = kzalloc(sizeof(struct intel_connector), GFP_KERNEL);
        if (!intel_connector) {
                kfree(intel_lvds);
-               return;
+               return false;
        }
 
        if (!HAS_PCH_SPLIT(dev)) {
@@ -1026,7 +1026,7 @@ out:
        /* keep the LVDS connector */
        dev_priv->int_lvds_connector = connector;
        drm_sysfs_connector_add(connector);
-       return;
+       return true;
 
 failed:
        DRM_DEBUG_KMS("No LVDS modes found, disabling.\n");
@@ -1034,4 +1034,5 @@ failed:
        drm_encoder_cleanup(encoder);
        kfree(intel_lvds);
        kfree(intel_connector);
+       return false;
 }