ACPI: EC: Add wait for irq storm

Merge of poll and irq modes accelerated EC transaction, so
that keyboard starts to suffer again. Add msleep(1) into
transaction path for the storm to allow keyboard controller
to do its job.

Reference: http://bugzilla.kernel.org/show_bug.cgi?id=14747

Signed-off-by: Alexey Starikovskiy <astarikovskiy@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/ec.c

@@ -259,7 +259,6 @@ static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
 		clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
 	spin_unlock_irqrestore(&ec->curr_lock, tmp);
 	ret = ec_poll(ec);
-	pr_debug(PREFIX "transaction end\n");
 	spin_lock_irqsave(&ec->curr_lock, tmp);
 	ec->curr = NULL;
 	spin_unlock_irqrestore(&ec->curr_lock, tmp);
@@ -316,13 +315,15 @@ static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
 	/* check if we received SCI during transaction */
 	ec_check_sci_sync(ec, acpi_ec_read_status(ec));
 	if (test_bit(EC_FLAGS_GPE_STORM, &ec->flags)) {
+		msleep(1);
 		/* it is safe to enable GPE outside of transaction */
 		acpi_enable_gpe(NULL, ec->gpe);
 	} else if (t->irq_count > ACPI_EC_STORM_THRESHOLD) {
 		pr_info(PREFIX "GPE storm detected, "
 			"transactions will use polling mode\n");
 		set_bit(EC_FLAGS_GPE_STORM, &ec->flags);
 	}
+	pr_debug(PREFIX "transaction end\n");
 end:
 	if (ec->global_lock)
 		acpi_release_global_lock(glk);