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).
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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