From: Aaron Ma aaron.ma@canonical.com
commit 720ef73d1a239e33c3ad8fac356b9b1348e68aaf upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/platform/x86/thinkpad_acpi.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/platform/x86/thinkpad_acpi.c +++ b/drivers/platform/x86/thinkpad_acpi.c @@ -6829,8 +6829,10 @@ static int __init tpacpi_query_bcl_level 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)) {