msm: kgsl: enable CPU IRQ while suspending context

Make sure that CPU interrupt is enabled before calling adreno
suspend_context when moving from NAP/SLEEP to SLUMBER state.
We send commands to GPU in adreno_drawctxt_switch() which will generate
GPU interrupt. Since CPU interrupt is not enabled, adreno_idle() will
fail because pending interrupt will not be served by CPU this causes
false GPU hang.

CRs-Fixed: 547813

Change-Id: Ia4b730b8f8cda1e820f571ffb7ddb00336ca1a8c
Signed-off-by: Gaurav Gagrani <ggagrani@codeaurora.org>

drivers/gpu/msm/kgsl_pwrctrl.c

@@ -1,4 +1,4 @@
-/* Copyright (c) 2010-2013, The Linux Foundation. All rights reserved.
+/* Copyright (c) 2010-2014, The Linux Foundation. All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 and
@@ -1448,6 +1448,7 @@ _slumber(struct kgsl_device *device)
 		del_timer_sync(&device->idle_timer);
 		/* make sure power is on to stop the device*/
 		kgsl_pwrctrl_enable(device);
+		kgsl_pwrctrl_irq(device, KGSL_PWRFLAGS_ON);
 		device->ftbl->suspend_context(device);
 		device->ftbl->stop(device);
 		_sleep_accounting(device);