1 files changed, 12 insertions, 0 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_connectors.c b/drivers/gpu/drm/radeon/radeon_connectors.c
index 8da06e17ff27..20161567dbff 100644
--- a/drivers/gpu/drm/radeon/radeon_connectors.c
+++ b/drivers/gpu/drm/radeon/radeon_connectors.c
@@ -208,6 +208,18 @@ static struct drm_display_mode *radeon_fp_native_mode(struct drm_encoder *encode
                 drm_mode_set_name(mode);
 
                 DRM_DEBUG("Adding native panel mode %s\n", mode->name);
+        } else if (native_mode->hdisplay != 0 &&
+                   native_mode->vdisplay != 0) {
+                /* mac laptops without an edid */
+                /* Note that this is not necessarily the exact panel mode,
+                 * but an approximation based on the cvt formula.  For these
+                 * systems we should ideally read the mode info out of the
+                 * registers or add a mode table, but this works and is much
+                 * simpler.
+                 */
+                mode = drm_cvt_mode(dev, native_mode->hdisplay, native_mode->vdisplay, 60, true, false, false);
+                mode->type = DRM_MODE_TYPE_PREFERRED | DRM_MODE_TYPE_DRIVER;
+                DRM_DEBUG("Adding cvt approximation of native panel mode %s\n", mode->name);
         }
         return mode;
 }