1 files changed, 9 insertions, 0 deletions

diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 599e58168631..9e80207c96a2 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -315,6 +315,15 @@ static unsigned long quick_pit_calibrate(void)
         outb(0xff, 0x42);
         outb(0xff, 0x42);
 
+        /*
+         * The PIT starts counting at the next edge, so we
+         * need to delay for a microsecond. The easiest way
+         * to do that is to just read back the 16-bit counter
+         * once from the PIT.
+         */
+        inb(0x42);
+        inb(0x42);
+
         if (pit_expect_msb(0xff)) {
                 int i;
                 u64 t1, t2, delta;