Revert "[Ozone-DRM] Modeset when re-mapping windows to controllers"

This reverts commit a8c88bddec37b978604ba6bf0399e16dd2146729.

Causing black screen on daisy, spring, minnie.

BUG=532765, 511446
CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel

Review URL: https://codereview.chromium.org/1353873003 .

Cr-Commit-Position: refs/branch-heads/2454@{#486}
Cr-Branched-From: 12bfc3360892ec53cd00fc239a47e5298beb063b-refs/heads/master@{#338390}

1 files changed, 3 insertions, 13 deletions

diff --git a/ui/ozone/platform/drm/gpu/screen_manager.cc b/ui/ozone/platform/drm/gpu/screen_manager.cc
index 72a14a1..4b4d3f1 100644
--- a/ui/ozone/platform/drm/gpu/screen_manager.cc
+++ b/ui/ozone/platform/drm/gpu/screen_manager.cc
@@ -292,20 +292,10 @@ void ScreenManager::UpdateControllerToWindowMapping() {
   // Apply the new mapping to all windows.
   for (auto pair : window_map_) {
     auto it = window_to_controller_map.find(pair.second);
-    HardwareDisplayController* controller = nullptr;
     if (it != window_to_controller_map.end())
-      controller = it->second;
-
-    bool should_enable =
-        controller && pair.second->GetController() != controller;
-    pair.second->SetController(controller);
-
-    // If we're moving windows between controllers modeset the controller
-    // otherwise the controller may be waiting for a page flip while the window
-    // tries to schedule another buffer.
-    if (should_enable)
-      EnableController(controller, controller->origin(),
-                       controller->get_mode());
+      pair.second->SetController(it->second);
+    else
+      pair.second->SetController(nullptr);
   }
 }