Re: [Debug 2/2] x86/PCI/ACPI: Relax ACPI resource descriptor checks to work around BIOS bugs

Jiang Liu
2015-03-04T02:29:22Z

On 2015/3/3 23:18, Bjorn Helgaas wrote:
> On Mon, Mar 2, 2015 at 10:25 PM, Jiang Liu <jiang.liu@linux.intel.com> wrote:
>> Some BIOSes report incorrect length for ACPI address space descriptors,
>> so relax the checks to avoid regressions.
>>
>> Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
>
> It'd be nice to have a DSDT archived and referenced in this changelog
> for future reference. This sounds similar to previous issues:
Hi all,
Could anybody help to dump an ACPI table from those failure
systems so we could archive it?
Thanks!
Gerry

>
> 3162b6f0c5e1 ("PNPACPI: truncate _CRS windows with _LEN > _MAX - _MIN + 1")
> d558b483d5a7 ("x86/PCI: truncate _CRS windows with _LEN > _MAX - _MIN + 1")
> f238b414a74a ("PNPACPI: compute Address Space length rather than using _LEN")
> 48728e077480 ("x86/PCI: compute Address Space length rather than using _LEN")
>
> I assume your work fixes both these paths and avoids the issues we fixed above.
>
>> ---
>> drivers/acpi/resource.c | 4 +++-
>> 1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/acpi/resource.c b/drivers/acpi/resource.c
>> index c723668e3e27..5589a6e2a023 100644
>> --- a/drivers/acpi/resource.c
>> +++ b/drivers/acpi/resource.c
>> @@ -42,8 +42,10 @@ static bool acpi_dev_resource_len_valid(u64 start, u64 end, u64 len, bool io)
>> * CHECKME: len might be required to check versus a minimum
>> * length as well. 1 for io is fine, but for memory it does
>> * not make any sense at all.
>> + * Note: some BIOSes report incorrect length for ACPI address space
>> + * descriptor, so remove check of 'reslen == len' to avoid regression.
>> */
>> - if (len && reslen && reslen == len && start <= end)
>> + if (len && reslen && start <= end)
>> return true;
>>
>> pr_debug("ACPI: invalid or unassigned resource %s [%016llx - %016llx] length [%016llx]\n",
>> --
>> 1.7.10.4
>>