Enable dark_resume_always workaround if the wake-on-packets flag is set

chrome/browser/chromeos/power/light_bar.cc

 // Copyright 2014 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 "chrome/browser/chromeos/power/light_bar.h"
 
 #include <cstring>  // needed for strlen()
 
 #include "base/command_line.h"
 #include "base/files/file_util.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
 #include "chromeos/chromeos_switches.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
 
 namespace chromeos {
 
 namespace {
 const int kDarkSuspendDelaySeconds = 4;
 const char kLightBarControlPath[] =
     "/sys/devices/platform/cros_ec_lpc.0/cros-ec-dev.0/chromeos/cros_ec/"
     "lightbar/sequence";
 const char kKonamiCommand[] = "KONAMI";
 
+// TODO(chirantan): These are used by a temporary workaround for lucid sleep and
+// should be removed once the proper implementation is ready (crbug.com/414949).
+const char kDarkResumeAlwaysFile[] = "/sys/power/dark_resume_always";
+const char kEnableDarkResumeAlways[] = "1";
+
 }  // namespace
 
 LightBar::LightBar()
     : control_path_(base::FilePath(kLightBarControlPath)),
       has_light_bar_(base::PathIsWritable(control_path_)) {
   DBusThreadManager::Get()->GetPowerManagerClient()->AddObserver(this);
+
+  // Until the kernel can properly detect the wakeup source, we need to use a
+  // hack to tell the kernel to always enter dark resume.  Chrome can then
+  // detect any user activity and have the power manager transition out of dark
+  // resume into regular resume.  We don't care if the write succeeds or not
+  // because most devices will not have this file.
+  //
+  // TODO(chirantan): Remove this once we can properly detect the wakeup
+  // source (crbug.com/414949).
+  base::WriteFile(base::FilePath(kDarkResumeAlwaysFile),
+                  kEnableDarkResumeAlways,
+                  strlen(kEnableDarkResumeAlways));
 }
 
 LightBar::~LightBar() {
   DBusThreadManager::Get()->GetPowerManagerClient()->RemoveObserver(this);
 }
 
 void LightBar::DarkSuspendImminent() {
   // The plan is to track the progress of push events and then re-suspend as
   // soon as we know they have been processed.  In the meanwhile, we can hack
   // around this by just having the light bar delay for a long time so that
@@ skipping 10 matching lines @@
 
   if (!has_light_bar_)
     return;
 
   if (base::WriteFile(control_path_, kKonamiCommand, strlen(kKonamiCommand)) !=
       static_cast<int>(strlen(kKonamiCommand)))
     PLOG(WARNING) << "Unable to flash light bar during dark resume.";
 }
 
 }  // namespace chromeos