ACPI: EC: Some hardware requires burst mode to operate properly

Burst mode temporary (50 ms) locks EC to do only transactions with
driver, without it some hardware returns abstract garbage.

Reference: http://bugzilla.kernel.org/show_bug.cgi?id=9341

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

drivers/acpi/ec.c

@@ -575,6 +575,8 @@ acpi_ec_space_handler(u32 function, acpi_physical_address address,
 	if (bits != 8 && acpi_strict)
 		return AE_BAD_PARAMETER;
 
+	acpi_ec_burst_enable(ec);
+
 	if (function == ACPI_READ) {
 		result = acpi_ec_read(ec, address, &temp);
 		*value = temp;
@@ -594,6 +596,8 @@ acpi_ec_space_handler(u32 function, acpi_physical_address address,
 		}
 	}
 
+	acpi_ec_burst_disable(ec);
+
 	switch (result) {
 	case -EINVAL:
 		return AE_BAD_PARAMETER;