chromeos: Turn off displays on suspend

ui/display/chromeos/display_configurator.cc

Index: ui/display/chromeos/display_configurator.cc
diff --git a/ui/display/chromeos/display_configurator.cc b/ui/display/chromeos/display_configurator.cc
index e1def2037131a0edf7611ec5def3d6eca7f2aba3..03ac4140e4ee18a15ee58d0071a545c3c1e7fa5a 100644
--- a/ui/display/chromeos/display_configurator.cc
+++ b/ui/display/chromeos/display_configurator.cc
@@ -35,12 +35,6 @@ typedef std::vector<const DisplayMode*> DisplayModeList;
 // |configure_timer_|.
 const int kConfigureDelayMs = 500;
 
-// The delay spent before reading the display configuration after coming out of
-// suspend. While coming out of suspend the display state may be updating. This
-// is used to wait until the hardware had a chance to update the display state
-// such that we read an up to date state.
-const int kResumeDelayMs = 500;
-
 // The EDID specification marks the top bit of the manufacturer id as reserved.
 const int16_t kReservedManufacturerID = static_cast<int16_t>(1 << 15);
 
@@ -476,8 +470,9 @@ DisplayConfigurator::DisplayConfigurator()
       current_power_state_(chromeos::DISPLAY_POWER_ALL_ON),
       requested_display_state_(MULTIPLE_DISPLAY_STATE_INVALID),
       requested_power_state_(chromeos::DISPLAY_POWER_ALL_ON),
-      requested_power_state_change_(false),
-      requested_power_flags_(kSetDisplayPowerNoFlags),
+      pending_power_state_(chromeos::DISPLAY_POWER_ALL_ON),
+      pending_power_state_change_(false),
+      pending_power_flags_(kSetDisplayPowerNoFlags),
       force_configure_(false),
       next_display_protection_client_id_(1),
       display_externally_controlled_(false),
@@ -844,6 +839,24 @@ void DisplayConfigurator::PrepareForExit() {
   configure_display_ = false;
 }
 
+void DisplayConfigurator::SetDisplayPowerInternal(
+    chromeos::DisplayPowerState power_state,
+    int flags,
+    const ConfigurationCallback& callback) {
+  if (power_state == current_power_state_ &&
+      !(flags & kSetDisplayPowerForceProbe)) {
+    callback.Run(true);
+    return;
+  }
+
+  pending_power_state_ = power_state;
+  pending_power_state_change_ = true;
+  pending_power_flags_ = flags;
+  queued_configuration_callbacks_.push_back(callback);
+
+  RunPendingConfiguration();
+}
+
 void DisplayConfigurator::SetDisplayPower(
     chromeos::DisplayPowerState power_state,
     int flags,
@@ -857,18 +870,9 @@ void DisplayConfigurator::SetDisplayPower(
           << DisplayPowerStateToString(power_state) << " flags=" << flags
           << ", configure timer="
           << (configure_timer_.IsRunning() ? "Running" : "Stopped");
-  if (power_state == requested_power_state_ &&
-      !(flags & kSetDisplayPowerForceProbe)) {
-    callback.Run(true);
-    return;
-  }
 
   requested_power_state_ = power_state;
-  requested_power_state_change_ = true;
-  requested_power_flags_ = flags;
-  queued_configuration_callbacks_.push_back(callback);
-
-  RunPendingConfiguration();
+  SetDisplayPowerInternal(requested_power_state_, flags, callback);
 }
 
 void DisplayConfigurator::SetDisplayMode(MultipleDisplayState new_state) {
@@ -931,38 +935,31 @@ void DisplayConfigurator::RemoveObserver(Observer* observer) {
 
 void DisplayConfigurator::SuspendDisplays(
     const ConfigurationCallback& callback) {
-  // If the display is off due to user inactivity and there's only a single
-  // internal display connected, switch to the all-on state before
-  // suspending.  This shouldn't be very noticeable to the user since the
-  // backlight is off at this point, and doing this lets us resume directly
-  // into the "on" state, which greatly reduces resume times.
-  if (requested_power_state_ == chromeos::DISPLAY_POWER_ALL_OFF) {
-    SetDisplayPower(chromeos::DISPLAY_POWER_ALL_ON,
-                    kSetDisplayPowerOnlyIfSingleInternalDisplay, callback);
-
-    // We need to make sure that the monitor configuration we just did actually
-    // completes before we return, because otherwise the X message could be
-    // racing with the HandleSuspendReadiness message.
-    native_display_delegate_->SyncWithServer();
-  } else {
-    callback.Run(true);
-  }
-
   displays_suspended_ = true;
 
   // Stop |configure_timer_| because we will force probe and configure all the
   // displays at resume time anyway.
   configure_timer_.Stop();
+
+  // Turn off the displays for suspend. This way, if we wake up for lucid sleep,
+  // the displays will not turn on (all displays should be off for lucid sleep
+  // unless explicitly requested by lucid sleep code). Use
+  // SetDisplayPowerInternal so requested_power_state_ is maintained.
+  SetDisplayPowerInternal(chromeos::DISPLAY_POWER_ALL_OFF,
+                          kSetDisplayPowerNoFlags, callback);
+
+  // We need to make sure that the monitor configuration we just did actually
+  // completes before we return.
+  native_display_delegate_->SyncWithServer();
 }
 
 void DisplayConfigurator::ResumeDisplays() {
   displays_suspended_ = false;
 
-  configure_timer_.Start(
-      FROM_HERE,
-      base::TimeDelta::FromMilliseconds(kResumeDelayMs),
-      base::Bind(&DisplayConfigurator::RestoreRequestedPowerStateAfterResume,
-                 base::Unretained(this)));
+  // If requested_power_state_ is ALL_OFF due to idle suspend, powerd will turn
+  // the display power on when it enables the backlight.
+  SetDisplayPower(requested_power_state_, kSetDisplayPowerNoFlags,
+                  base::Bind(&DoNothing));
 }
 
 void DisplayConfigurator::ConfigureDisplays() {
@@ -988,7 +985,7 @@ void DisplayConfigurator::RunPendingConfiguration() {
 
   configuration_task_.reset(new UpdateDisplayConfigurationTask(
       native_display_delegate_.get(), layout_manager_.get(),
-      requested_display_state_, requested_power_state_, requested_power_flags_,
+      requested_display_state_, pending_power_state_, pending_power_flags_,
       0, force_configure_, base::Bind(&DisplayConfigurator::OnConfigured,
                                       weak_ptr_factory_.GetWeakPtr())));
   configuration_task_->set_virtual_display_snapshots(
@@ -997,8 +994,8 @@ void DisplayConfigurator::RunPendingConfiguration() {
   // Reset the flags before running the task; otherwise it may end up scheduling
   // another configuration.
   force_configure_ = false;
-  requested_power_flags_ = kSetDisplayPowerNoFlags;
-  requested_power_state_change_ = false;
+  pending_power_flags_ = kSetDisplayPowerNoFlags;
+  pending_power_state_change_ = false;
   requested_display_state_ = MULTIPLE_DISPLAY_STATE_INVALID;
 
   DCHECK(in_progress_configuration_callbacks_.empty());
@@ -1038,7 +1035,7 @@ void DisplayConfigurator::OnConfigured(
     // gets updated as well since the last requested value may have been
     // dependent on certain conditions (ie: if only the internal monitor was
     // present).
-    if (!requested_power_state_change_)
+    if (!pending_power_state_change_)
       requested_power_state_ = new_power_state;
 
     if (old_power_state != current_power_state_)
@@ -1072,7 +1069,7 @@ bool DisplayConfigurator::ShouldRunConfigurationTask() const {
     return true;
 
   // Schedule if there is a request to change the power state.
-  if (requested_power_state_change_)
+  if (pending_power_state_change_)
     return true;
 
   return false;
@@ -1092,13 +1089,6 @@ void DisplayConfigurator::CallAndClearQueuedCallbacks(bool success) {
   queued_configuration_callbacks_.clear();
 }
 
-void DisplayConfigurator::RestoreRequestedPowerStateAfterResume() {
-  // Force probing to ensure that we pick up any changes that were made while
-  // the system was suspended.
-  SetDisplayPower(requested_power_state_, kSetDisplayPowerForceProbe,
-                  base::Bind(&DoNothing));
-}
-
 void DisplayConfigurator::NotifyDisplayStateObservers(
     bool success,
     MultipleDisplayState attempted_state) {