[Nouveau] [PATCH 5/8] acpi: Check returned object type by Optimus _DSM locally

[Pierre Moreau]

> On 26 May 2015, at 00:39, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
> 
>> On Mon, May 25, 2015 at 6:22 PM, Pierre Moreau <pierre.morrow at free.fr> wrote:
>> Most _DSM will return an integer value of 0x80000002 when given an unknown
>> UUID, revision ID or function ID. Checking locally allows us to differentiate
>> that case from other ACPI errors, and to not report a "failed to evaluate _DSM"
>> if 0x80000002 is returned which was confusing.
>> 
>> Signed-off-by: Pierre Moreau <pierre.morrow at free.fr>
>> ---
>> drm/nouveau/nouveau_acpi.c | 15 ++++++++++++---
>> 1 file changed, 12 insertions(+), 3 deletions(-)
>> 
>> diff --git a/drm/nouveau/nouveau_acpi.c b/drm/nouveau/nouveau_acpi.c
>> index 073f7d7..7aeaf7d 100644
>> --- a/drm/nouveau/nouveau_acpi.c
>> +++ b/drm/nouveau/nouveau_acpi.c
>> @@ -88,12 +88,12 @@ static int nouveau_evaluate_optimus_dsm(acpi_handle handle, int func, int arg, u
>>        for (i = 0; i < 4; i++)
>>                args_buff[i] = (arg >> i * 8) & 0xFF;
>> 
>> -       obj = acpi_evaluate_dsm_typed(handle, nouveau_op_dsm_muid, nouveau_op_dsm_rid,
>> -                                     func, &argv4, ACPI_TYPE_BUFFER);
>> +       obj = acpi_evaluate_dsm(handle, nouveau_op_dsm_muid, nouveau_op_dsm_rid,
>> +                               func, &argv4);
>>        if (!obj) {
>>                acpi_handle_info(handle, "failed to evaluate _DSM\n");
>>                return AE_ERROR;
>> -       } else {
>> +       } else if (obj->type == ACPI_TYPE_BUFFER) {
>>                if (!result && obj->buffer.length == 4) {
>>                        *result  = obj->buffer.pointer[0];
>>                        *result |= (obj->buffer.pointer[1] << 8);
>> @@ -101,6 +101,15 @@ static int nouveau_evaluate_optimus_dsm(acpi_handle handle, int func, int arg, u
>>                        *result |= (obj->buffer.pointer[3] << 24);
>>                }
>>                ACPI_FREE(obj);
>> +       } else if (obj->type == ACPI_TYPE_INTEGER &&
>> +                  obj->integer.value == 0x80000002) {
>> +               acpi_handle_debug(handle, "failed to query Optimus _DSM\n");
>> +               ACPI_FREE(obj);
>> +               return -ENODEV;
> 
> should this be AE_ERROR?

I would say no, because ACPI was parsed correctly, just that we didn't it give the correct arguments, or rather, the _DSM we tested isn't an Optimus one, but it could a mux or gmux. And I used ENODEV as it is the value returned by nouveau_evaluate_mux_dsm in the same context. 

> 
>> +       } else {
>> +               acpi_handle_err(handle, "unexpected returned value by Optimus _DSM\n");
>> +               ACPI_FREE(obj);
>> +               return AE_ERROR;
>>        }
>> 
>>        return 0;
>> --
>> 2.4.1
>> 
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