Re: [PATCH 34/40] drm/amd/display/amdgpu_dm/amdgpu_dm_helpers: Use 'gnu_printf' format notation

[Christian König]

Am 01.12.20 um 19:42 schrieb Alex Deucher:
> On Thu, Nov 26, 2020 at 8:44 AM Lee Jones <lee.jones@xxxxxxxxxx> wrote:
> > Fixes the following W=1 kernel build warning(s):
> >
> >   drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm_helpers.c: In function ‘dm_dtn_log_append_v’:
> >   drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm_helpers.c:345:2: warning: function ‘dm_dtn_log_append_v’ might be a candidate for ‘gnu_printf’ format attribute [-Wsuggest-attribute=format]
> >   drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm_helpers.c:375:3: warning: function ‘dm_dtn_log_append_v’ might be a candidate for ‘gnu_printf’ format attribute [-Wsuggest-attribute=format]
> >
> > Cc: Harry Wentland <harry.wentland@xxxxxxx>
> > Cc: Leo Li <sunpeng.li@xxxxxxx>
> > Cc: Alex Deucher <alexander.deucher@xxxxxxx>
> > Cc: "Christian König" <christian.koenig@xxxxxxx>
> > Cc: David Airlie <airlied@xxxxxxxx>
> > Cc: Daniel Vetter <daniel@xxxxxxxx>
> > Cc: amd-gfx@xxxxxxxxxxxxxxxxxxxxx
> > Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
> > Signed-off-by: Lee Jones <lee.jones@xxxxxxxxxx>
> > ---
> >   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c | 1 +
> >   1 file changed, 1 insertion(+)
> >
> > diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
> > index b7d7ec3ba00d7..24a81642baa26 100644
> > --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
> > +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
> > @@ -318,6 +318,7 @@ void dm_dtn_log_begin(struct dc_context *ctx,
> >          dm_dtn_log_append_v(ctx, log_ctx, "%s", msg);
> >   }
> >
> > +__printf(3, 4)
> Can you expand a bit on what this does?

Been a while since I looked into something like this, but IIRC this 
means that parameter 3 (msg) is considered a printf format string and 
the types of parameter 4 and following checked against that.

Looks correct to me.

Christian.

> Alex
>
> >   void dm_dtn_log_append_v(struct dc_context *ctx,
> >          struct dc_log_buffer_ctx *log_ctx,
> >          const char *msg, ...)
> > --
> > 2.25.1
> >
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