[PATCH] sky2: poke coalescing timer to fix hang

Need to restart the interrupt coalescing timer after clearing the interrupt,
to avoid races with interrupt timer and processing.

Patch from Carl-Daniel Halfinger

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>

drivers/net/sky2.c

@@ -1895,6 +1895,17 @@ static int sky2_poll(struct net_device *dev0, int *budget)
 
 	sky2_write32(hw, STAT_CTRL, SC_STAT_CLR_IRQ);
 
+	/*
+	 * Kick the STAT_LEV_TIMER_CTRL timer.
+	 * This fixes my hangs on Yukon-EC (0xb6) rev 1.
+	 * The if clause is there to start the timer only if it has been
+	 * configured correctly and not been disabled via ethtool.
+	 */
+	if (sky2_read8(hw, STAT_LEV_TIMER_CTRL) == TIM_START) {
+		sky2_write8(hw, STAT_LEV_TIMER_CTRL, TIM_STOP);
+		sky2_write8(hw, STAT_LEV_TIMER_CTRL, TIM_START);
+	}
+
 	hwidx = sky2_read16(hw, STAT_PUT_IDX);
 	BUG_ON(hwidx >= STATUS_RING_SIZE);
 	rmb();