1 files changed, 18 insertions, 5 deletions

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index dae976f51d83..69bcc42a0e44 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -9654,11 +9654,22 @@ intel_pipe_config_compare(struct drm_device *dev,
         PIPE_CONF_CHECK_I(pipe_src_w);
         PIPE_CONF_CHECK_I(pipe_src_h);
 
-        PIPE_CONF_CHECK_I(gmch_pfit.control);
-        /* pfit ratios are autocomputed by the hw on gen4+ */
-        if (INTEL_INFO(dev)->gen < 4)
-                PIPE_CONF_CHECK_I(gmch_pfit.pgm_ratios);
-        PIPE_CONF_CHECK_I(gmch_pfit.lvds_border_bits);
+        /*
+         * FIXME: BIOS likes to set up a cloned config with lvds+external
+         * screen. Since we don't yet re-compute the pipe config when moving
+         * just the lvds port away to another pipe the sw tracking won't match.
+         *
+         * Proper atomic modesets with recomputed global state will fix this.
+         * Until then just don't check gmch state for inherited modes.
+         */
+        if (!PIPE_CONF_QUIRK(PIPE_CONFIG_QUIRK_INHERITED_MODE)) {
+                PIPE_CONF_CHECK_I(gmch_pfit.control);
+                /* pfit ratios are autocomputed by the hw on gen4+ */
+                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.enabled);
         if (current_config->pch_pfit.enabled) {
                 PIPE_CONF_CHECK_I(pch_pfit.pos);
@@ -11616,6 +11627,8 @@ static void intel_modeset_readout_hw_state(struct drm_device *dev)
                             base.head) {
                 memset(&crtc->config, 0, sizeof(crtc->config));
 
+                crtc->config.quirks |= PIPE_CONFIG_QUIRK_INHERITED_MODE;
+
                 crtc->active = dev_priv->display.get_pipe_config(crtc,
                                                                  &crtc->config);