[PATCH] ACPI: Read TSC upon resume

[Sameer Nanda <snanda@chromium.org>]

Read the TSC upon resuming and print it out. This is useful
in helping figure out amount of time spent in the BIOS when
resuming from suspend.

Change-Id: I1d6a32bd62421becddecd152d561763e5f3e1101
Signed-off-by: Sameer Nanda <snanda@chromium.org>
---
 drivers/acpi/sleep.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c
index c0fed2e..f0588fa 100644
--- a/drivers/acpi/sleep.c
+++ b/drivers/acpi/sleep.c
@@ -214,6 +214,7 @@ static int acpi_suspend_enter(suspend_state_t pm_state)
 	acpi_status status = AE_OK;
 	unsigned long flags = 0;
 	u32 acpi_state = acpi_target_sleep_state;
+	u64 tsc;
 
 	ACPI_FLUSH_CPU_CACHE();
 
@@ -235,6 +236,9 @@ static int acpi_suspend_enter(suspend_state_t pm_state)
 
 	case ACPI_STATE_S3:
 		do_suspend_lowlevel();
+		rdtscll(tsc);
+		printk(KERN_INFO "TSC at resume: %llu\n",
+				(unsigned long long)tsc);
 		break;
 	}
 
-- 
1.7.1