4 files changed, 15 insertions, 4 deletions

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index bae38acf44dc..8be30917bce3 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -3478,8 +3478,11 @@ static bool intel_crtc_mode_fixup(struct drm_crtc *crtc,
                         return false;
         }
 
-        /* All interlaced capable intel hw wants timings in frames. */
-        drm_mode_set_crtcinfo(adjusted_mode, 0);
+        /* All interlaced capable intel hw wants timings in frames. Note though
+         * that intel_lvds_mode_fixup does some funny tricks with the crtc
+         * timings, so we need to be careful not to clobber these.*/
+        if (!(adjusted_mode->private_flags & INTEL_MODE_CRTC_TIMINGS_SET))
+                drm_mode_set_crtcinfo(adjusted_mode, 0);
 
         return true;
 }
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 5a14149b3794..715afa153025 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -105,6 +105,10 @@
 #define INTEL_MODE_PIXEL_MULTIPLIER_SHIFT (0x0)
 #define INTEL_MODE_PIXEL_MULTIPLIER_MASK (0xf << INTEL_MODE_PIXEL_MULTIPLIER_SHIFT)
 #define INTEL_MODE_DP_FORCE_6BPC (0x10)
+/* This flag must be set by the encoder's mode_fixup if it changes the crtc
+ * timings in the mode to prevent the crtc fixup from overwriting them.
+ * Currently only lvds needs that. */
+#define INTEL_MODE_CRTC_TIMINGS_SET (0x20)
 
 static inline void
 intel_mode_set_pixel_multiplier(struct drm_display_mode *mode,
diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
index 95db2e988227..30e2c82101de 100644
--- a/drivers/gpu/drm/i915/intel_lvds.c
+++ b/drivers/gpu/drm/i915/intel_lvds.c
@@ -187,6 +187,8 @@ centre_horizontally(struct drm_display_mode *mode,
 
         mode->crtc_hsync_start = mode->crtc_hblank_start + sync_pos;
         mode->crtc_hsync_end = mode->crtc_hsync_start + sync_width;
+
+        mode->private_flags |= INTEL_MODE_CRTC_TIMINGS_SET;
 }
 
 static void
@@ -208,6 +210,8 @@ centre_vertically(struct drm_display_mode *mode,
 
         mode->crtc_vsync_start = mode->crtc_vblank_start + sync_pos;
         mode->crtc_vsync_end = mode->crtc_vsync_start + sync_width;
+
+        mode->private_flags |= INTEL_MODE_CRTC_TIMINGS_SET;
 }
 
 static inline u32 panel_fitter_scaling(u32 source, u32 target)
@@ -283,6 +287,8 @@ static bool intel_lvds_mode_fixup(struct drm_encoder *encoder,
         for_each_pipe(pipe)
                 I915_WRITE(BCLRPAT(pipe), 0);
 
+        drm_mode_set_crtcinfo(adjusted_mode, 0);
+
         switch (intel_lvds->fitting_mode) {
         case DRM_MODE_SCALE_CENTER:
                 /*
diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index 230a141dbea3..48177ec4720e 100644
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -47,8 +47,6 @@ intel_fixed_panel_mode(struct drm_display_mode *fixed_mode,
         adjusted_mode->vtotal = fixed_mode->vtotal;
 
         adjusted_mode->clock = fixed_mode->clock;
-
-        drm_mode_set_crtcinfo(adjusted_mode, 0);
 }
 
 /* adjusted_mode has been preset to be the panel's fixed mode */