Matching modes for mirroring should preserve interlacing.

chromeos/display/output_configurator.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chromeos/display/output_configurator.h"
 
 #include <cmath>
 
 #include <X11/Xatom.h>
 #include <X11/Xlib.h>
@@ skipping 1052 matching lines @@
     bool is_native_aspect_ratio =
         external_native_mode->width * external_mode->height ==
         external_native_mode->height * external_mode->width;
     if (preserve_aspect && !is_native_aspect_ratio)
       continue;  // Allow only aspect ratio preserving modes for mirroring
 
     // Try finding exact match
     for (int j = 0; j < internal_info->nmode; j++) {
       internal_mode_id = internal_info->modes[j];
       XRRModeInfo* internal_mode = ModeInfoForID(screen, internal_mode_id);
+      bool is_internal_interlaced = internal_mode->modeFlags & RR_Interlace;
+      bool is_external_interlaced = external_mode->modeFlags & RR_Interlace;
       if (internal_mode->width == external_mode->width &&
-          internal_mode->height == external_mode->height) {
+          internal_mode->height == external_mode->height &&
+          is_internal_interlaced == is_external_interlaced) {
         *internal_mirror_mode = internal_mode_id;
         *external_mirror_mode = external_mode_id;
         return true;  // Mirror mode found
       }
     }
 
     // Try to create a matching internal output mode by panel fitting
     if (try_creating) {
       // We can downscale by 1.125, and upscale indefinitely
       // Downscaling looks ugly, so, can fit == can upscale
+      // Also, internal panels don't support fitting interlaced modes
       bool can_fit =
           internal_native_mode->width >= external_mode->width &&
-          internal_native_mode->height >= external_mode->height;
+          internal_native_mode->height >= external_mode->height &&
+          !(external_mode->modeFlags & RR_Interlace);
       if (can_fit) {
         XRRAddOutputMode(display, internal_output_id, external_mode_id);
         *internal_mirror_mode = *external_mirror_mode = external_mode_id;
         return true;  // Mirror mode created
       }
     }
   }
 
   return false;
 }
@@ skipping 258 matching lines @@
 // static
 RRMode OutputConfigurator::GetOutputNativeMode(
     const XRROutputInfo* output_info) {
   if (output_info->nmode <= 0)
     return None;
 
   return output_info->modes[0];
 }
 
 }  // namespace chromeos