faft: Disable dev screen short delay and tune ctrl-d delay for all devices.

The current ctrl-d delay is very short, just 2 seconds, for some fast devices,
like Lumpy. But on some slow or still under-development devices, the system
can't boot into the dev screen in 2 seconds. So we should increase this delay,
and also disable the dev screen short delay GBB flag to prevent timeout.

BUG=chromium-os:22601
TEST=Run firmwre_TryFwB/control.dev on Snow passed.

Change-Id: Ib345a89b6ff1e3d4b31b8532054262ead4e882ea
Reviewed-on: https://gerrit.chromium.org/gerrit/28781
Reviewed-by: Vic Yang <victoryang@chromium.org>
Commit-Ready: Tom Wai-Hong Tam <waihong@chromium.org>
Tested-by: Tom Wai-Hong Tam <waihong@chromium.org>
diff --git a/server/cros/faftsequence.py b/server/cros/faftsequence.py
index 1045d97..ae37897 100644
--- a/server/cros/faftsequence.py
+++ b/server/cros/faftsequence.py
@@ -86,7 +86,7 @@
     OTHER_ROOTFS_MAP = {'a':'5', 'b':'3', '2':'5', '4':'3', '3':'5', '5':'3'}
 
     # Delay between power-on and firmware screen.
-    FIRMWARE_SCREEN_DELAY = 2
+    FIRMWARE_SCREEN_DELAY = 5
     # Delay between passing firmware screen and text mode warning screen.
     TEXT_SCREEN_DELAY = 20
     # Delay of loading the USB kernel.
@@ -99,8 +99,6 @@
     EC_REBOOT_DELAY = 1
     # Delay between EC reboot and pressing power button
     POWER_BTN_DELAY = 0.5
-    # Delay between sending keystroke to firmware
-    FIRMWARE_KEY_DELAY = 0.5
     # Delay of EC software sync hash calculating time
     SOFTWARE_SYNC_DELAY = 6
 
@@ -248,6 +246,7 @@
         if not self._remote_infos['faft']['used']:
             raise error.TestError('The use_faft flag should be enabled.')
         self.clear_gbb_flags(self.GBB_FLAG_FORCE_DEV_SWITCH_ON)
+        self.clear_gbb_flags(self.GBB_FLAG_DEV_SCREEN_SHORT_DELAY)
         self.register_faft_template({
             'state_checker': (None),
             'userspace_action': (None),
@@ -769,7 +768,7 @@
             self.send_ctrl_d_to_dut()
         else:
             self.send_enter_to_dut()
-        time.sleep(self.FIRMWARE_KEY_DELAY)
+        time.sleep(self.FIRMWARE_SCREEN_DELAY)
         self.send_enter_to_dut()