1 files changed, 46 insertions, 0 deletions

diff --git a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
index 086e52af1bc7..1d296707ceda 100644
--- a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
+++ b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
@@ -437,7 +437,12 @@ int tilcdc_crtc_mode_valid(struct drm_crtc *crtc, struct drm_display_mode *mode)
 {
         struct tilcdc_drm_private *priv = crtc->dev->dev_private;
         unsigned int bandwidth;
+        uint32_t hbp, hfp, hsw, vbp, vfp, vsw;
 
+        /*
+         * check to see if the width is within the range that
+         * the LCD Controller physically supports
+         */
         if (mode->hdisplay > tilcdc_crtc_max_width(crtc))
                 return MODE_VIRTUAL_X;
 
@@ -448,6 +453,47 @@ int tilcdc_crtc_mode_valid(struct drm_crtc *crtc, struct drm_display_mode *mode)
         if (mode->vdisplay > 2048)
                 return MODE_VIRTUAL_Y;
 
+        DBG("Processing mode %dx%d@%d with pixel clock %d",
+                mode->hdisplay, mode->vdisplay,
+                drm_mode_vrefresh(mode), mode->clock);
+
+        hbp = mode->htotal - mode->hsync_end;
+        hfp = mode->hsync_start - mode->hdisplay;
+        hsw = mode->hsync_end - mode->hsync_start;
+        vbp = mode->vtotal - mode->vsync_end;
+        vfp = mode->vsync_start - mode->vdisplay;
+        vsw = mode->vsync_end - mode->vsync_start;
+
+        if ((hbp-1) & ~0x3ff) {
+                DBG("Pruning mode: Horizontal Back Porch out of range");
+                return MODE_HBLANK_WIDE;
+        }
+
+        if ((hfp-1) & ~0x3ff) {
+                DBG("Pruning mode: Horizontal Front Porch out of range");
+                return MODE_HBLANK_WIDE;
+        }
+
+        if ((hsw-1) & ~0x3ff) {
+                DBG("Pruning mode: Horizontal Sync Width out of range");
+                return MODE_HSYNC_WIDE;
+        }
+
+        if (vbp & ~0xff) {
+                DBG("Pruning mode: Vertical Back Porch out of range");
+                return MODE_VBLANK_WIDE;
+        }
+
+        if (vfp & ~0xff) {
+                DBG("Pruning mode: Vertical Front Porch out of range");
+                return MODE_VBLANK_WIDE;
+        }
+
+        if ((vsw-1) & ~0x3f) {
+                DBG("Pruning mode: Vertical Sync Width out of range");
+                return MODE_VSYNC_WIDE;
+        }
+
         /*
          * some devices have a maximum allowed pixel clock
          * configured from the DT