[PATCH 4.19 121/131] staging: vt6656: Power save stop wake_up_count wrap around.

[Greg Kroah-Hartman]

From: Malcolm Priestley <tvboxspy@xxxxxxxxx>

commit ea81c3486442f4643fc9825a2bb1b430b829bccd upstream.

conf.listen_interval can sometimes be zero causing wake_up_count
to wrap around up to many beacons too late causing
CTRL-EVENT-BEACON-LOSS as in.

wpa_supplicant[795]: message repeated 45 times: [..CTRL-EVENT-BEACON-LOSS ]

Fixes: 43c93d9bf5e2 ("staging: vt6656: implement power saving code.")
Cc: stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Malcolm Priestley <tvboxspy@xxxxxxxxx>
Link: https://lore.kernel.org/r/fce47bb5-7ca6-7671-5094-5c6107302f2b@xxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/staging/vt6656/int.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/staging/vt6656/int.c
+++ b/drivers/staging/vt6656/int.c
@@ -143,7 +143,8 @@ void vnt_int_process_data(struct vnt_pri
 				priv->wake_up_count =
 					priv->hw->conf.listen_interval;
 
-			--priv->wake_up_count;
+			if (priv->wake_up_count)
+				--priv->wake_up_count;
 
 			/* Turn on wake up to listen next beacon */
 			if (priv->wake_up_count == 1)