platform/x86: thinkpad_acpi: re-initialize ACPI buffer size when reuse

Evaluating ACPI _BCL could fail, then ACPI buffer size will be set to 0.
When reuse this ACPI buffer, AE_BUFFER_OVERFLOW will be triggered.

Re-initialize buffer size will make ACPI evaluate successfully.

Fixes: 46445b6b896fd ("thinkpad-acpi: fix handle locate for video and query of _BCL")
Signed-off-by: Aaron Ma <aaron.ma@canonical.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index 7cb3b71..e5a62fa 100644 (file)
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -6829,8 +6829,10 @@ static int __init tpacpi_query_bcl_levels(acpi_handle handle)
        list_for_each_entry(child, &device->children, node) {
                acpi_status status = acpi_evaluate_object(child->handle, "_BCL",
                                                          NULL, &buffer);
-               if (ACPI_FAILURE(status))
+               if (ACPI_FAILURE(status)) {
+                       buffer.length = ACPI_ALLOCATE_BUFFER;
                        continue;
+               }
 
                obj = (union acpi_object *)buffer.pointer;
                if (!obj || (obj->type != ACPI_TYPE_PACKAGE)) {