[PATCH] sony-laptop: Avoid oops on module unload for older laptops

[Lawrence Yiu <lawyiu.dev@gmail.com>]

Older VAIO laptops without the SN00 ACPI method will have the "handles"
variable unset. Return early from sony_nc_function_cleanup when "handles"
is null.

Signed-off-by: Lawrence Yiu <lawyiu.dev@gmail.com>
---
 drivers/platform/x86/sony-laptop.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/platform/x86/sony-laptop.c b/drivers/platform/x86/sony-laptop.c
index e9caa34..1dba359 100644
--- a/drivers/platform/x86/sony-laptop.c
+++ b/drivers/platform/x86/sony-laptop.c
@@ -1446,6 +1446,9 @@ static void sony_nc_function_cleanup(struct platform_device *pd)
 {
 	unsigned int i, result, bitmask, handle;
 
+	if (!handles)
+		return;
+
 	/* get enabled events and disable them */
 	sony_nc_int_call(sony_nc_acpi_handle, "SN01", NULL, &bitmask);
 	sony_nc_int_call(sony_nc_acpi_handle, "SN03", &bitmask, &result);
-- 
2.5.0