On 2018-09-24 06:22 PM, Nathan Chancellor wrote:
> On Mon, Sep 24, 2018 at 03:07:16PM -0700, Nick Desaulniers wrote:
>> On Fri, Sep 21, 2018 at 2:55 PM Nathan Chancellor
>> <natechancellor@xxxxxxxxx> wrote:
>>>
>>> Clang warns when one enumerated type is implicitly converted to another.
>>>
>>> drivers/gpu/drm/amd/amdgpu/../display/dc/dce/dce_aux.c:315:19: warning:
>>> implicit conversion from enumeration type 'enum
>>> aux_channel_operation_result' to different enumeration type 'enum
>>> aux_transaction_reply' [-Wenum-conversion]
>>> reply->status = AUX_CHANNEL_OPERATION_FAILED_HPD_DISCON;
>>> ~ ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>> drivers/gpu/drm/amd/amdgpu/../display/dc/i2caux/dce110/aux_engine_dce110.c:349:19:
>>> warning: implicit conversion from enumeration type 'enum
>>> aux_channel_operation_result' to different enumeration type 'enum
>>> aux_transaction_reply' [-Wenum-conversion]
>>> reply->status = AUX_CHANNEL_OPERATION_FAILED_HPD_DISCON;
>>> ~ ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>
>> I think the enum is actually wrong here. I think the correct fix would be:
>>
>> - reply->status = AUX_CHANNEL_OPERATION_FAILED_HPD_DISCON;
>> + reply->status = AUX_TRANSACTION_REPLY_HPD_DISCON;
>>
>> The identifiers are so similar, my guess was that it was easy to mix
>> them up. This looks like an actual bug to me, since the identifiers
>> have different values between the 2 different enums.
>>
>
> Hmmm interesting... I will be happy to send a v2 with your suggestion if
> one of the maintainers could confirm that to be the case (given DRM code
> is rather dense).
>
Nick is correct. We should keep the enum but assign AUX_TRANSACTION_REPLY_HPD_DISCON in dce_aux.c and aux_engine_dce110.c.
Thanks for spotting this.
Harry
> Thanks for the review!
> Nathan
>
>>>
>>> Instead of implicitly or explicitly converting between types, just
>>> change status to type uint8_t (since its max size is 255) which avoids
>>> this construct altogether.
>>>
>>> Reported-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
>>> Signed-off-by: Nathan Chancellor <natechancellor@xxxxxxxxx>
>>> ---
>>> drivers/gpu/drm/amd/display/dc/dc_ddc_types.h | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/gpu/drm/amd/display/dc/dc_ddc_types.h b/drivers/gpu/drm/amd/display/dc/dc_ddc_types.h
>>> index 05c8c31d8b31..97e1d4d19263 100644
>>> --- a/drivers/gpu/drm/amd/display/dc/dc_ddc_types.h
>>> +++ b/drivers/gpu/drm/amd/display/dc/dc_ddc_types.h
>>> @@ -79,7 +79,7 @@ enum aux_transaction_reply {
>>> };
>>>
>>> struct aux_reply_transaction_data {
>>> - enum aux_transaction_reply status;
>>> + uint8_t status;
>>> uint32_t length;
>>> uint8_t *data;
>>> };
>>> --
>>> 2.19.0
>>>
>>
>>
>> --
>> Thanks,
>> ~Nick Desaulniers
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