From: Jean Delvare Subject: ACPI, APEI: Fixup common access width firmware bug Many firmwares have a common register definition bug where 8-bit access width is specified for a 32-bit register. Ideally this should be fixed in the BIOS, but earlier versions of the kernel did not complain, so fix that up silently. Signed-off-by: Jean Delvare Cc: Gary Hade Cc: Len Brown Cc: stable@vger.kernel.org [3.4+] --- drivers/acpi/apei/apei-base.c | 5 +++++ 1 file changed, 5 insertions(+) --- linux-3.4.orig/drivers/acpi/apei/apei-base.c 2012-06-08 10:02:06.000000000 +0200 +++ linux-3.4/drivers/acpi/apei/apei-base.c 2012-06-08 10:04:16.503779775 +0200 @@ -586,6 +586,11 @@ static int apei_check_gar(struct acpi_ge } *access_bit_width = 1UL << (access_size_code + 2); + /* Fixup common BIOS bug */ + if (bit_width == 32 && bit_offset == 0 && (*paddr & 0x03) == 0 && + *access_bit_width < 32) + *access_bit_width = 32; + if ((bit_width + bit_offset) > *access_bit_width) { pr_warning(FW_BUG APEI_PFX "Invalid bit width + offset in GAR [0x%llx/%u/%u/%u/%u]\n",