output_configurator: Re-add DPMS call.

Removing those regresses idle suspend. Until we decide how to fix it
properly, let's add it back. Let's also add a message to explain the
use for that code so others don't fall into the same trap.

BUG=none
TEST=by hand, idle suspend/resume now works

Change-Id: I29c0a7f065ffbef2f8bbef148bd2fb1f0a3ebea8


Review URL: https://chromiumcodereview.appspot.com/11293056

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@165621 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 6 insertions, 1 deletions

diff --git a/chromeos/display/output_configurator.cc b/chromeos/display/output_configurator.cc
index 3b48576..795ef01 100644
--- a/chromeos/display/output_configurator.cc
+++ b/chromeos/display/output_configurator.cc
@@ -608,6 +608,11 @@ bool OutputConfigurator::ScreenPowerSet(bool power_on, bool all_displays) {
                    output_state_,
                    outputs,
                    connected_output_count_)) {
+      // Force the DPMS on since the driver doesn't always detect that it should
+      // turn on. This is needed when coming back from idle suspend.
+      CHECK(DPMSEnable(display));
+      CHECK(DPMSForceLevel(display, DPMSModeOn));
+
       XRRFreeScreenResources(screen);
       XUngrabServer(display);
       return true;
@@ -647,7 +652,7 @@ bool OutputConfigurator::ScreenPowerSet(bool power_on, bool all_displays) {
   }
 
   // Force the DPMS on since the driver doesn't always detect that it should
-  // turn on.
+  // turn on. This is needed when coming back from idle suspend.
   if (power_on) {
     CHECK(DPMSEnable(display));
     CHECK(DPMSForceLevel(display, DPMSModeOn));