Re: warning in omap_connector

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Tue, Jun 30, 2020 at 05:41:32PM +0300, Laurent Pinchart wrote:
> Hi Ville,
> 
> On Tue, Jun 30, 2020 at 05:39:02PM +0300, Ville Syrjälä wrote:
> > On Tue, Jun 30, 2020 at 10:19:23AM -0400, Alex Deucher wrote:
> > > On Tue, Jun 30, 2020 at 10:15 AM Ville Syrjälä wrote:
> > > >
> > > > On Tue, Jun 30, 2020 at 04:33:37PM +1000, Dave Airlie wrote:
> > > > > Hey Laurent,
> > > > >
> > > > > I merged drm-misc-next and noticed this, I'm not sure if it's
> > > > > collateral damage from something else changing or I've just missed it
> > > > > previously. 32-bit arm build.
> > > > >
> > > > >
> > > > > /home/airlied/devel/kernel/dim/src/drivers/gpu/drm/omapdrm/omap_connector.c:
> > > > > In function ‘omap_connector_mode_valid’:
> > > > > /home/airlied/devel/kernel/dim/src/drivers/gpu/drm/omapdrm/omap_connector.c:92:9:
> > > > > warning: braces around scalar initializer
> > > > >   struct drm_display_mode new_mode = { { 0 } };
> > > >
> > > > Probably fallout from my drm_display_mode shrinkage.
> > > >
> > > > Going to repeat my usual "just use {} when zero initializing
> > > > structs" recommendation. Avoids these stupid warnings, and IMO
> > > > also conveys the meaning better since there's no ambiguity
> > > > between zero initializing the whole struct vs. zero initializing
> > > > just the first member.
> > > 
> > > IIRC, LLVM and GCC treat these slightly differently.  We've generally
> > > just moved to using memset to avoid different compiler complaints when
> > > using these.
> > 
> > I don't particularly like memset() since the requirement to
> > pass the size just adds another way to screw things up. The
> > usual 'sizeof(*thing)' makes that slightly less of an issue,
> > but I've noticed that people often don't use that.
> > 
> > Another issue with memset() is that you then can end up with
> > a block of seemingly random collection of memsets()s between
> > the variable declarations and the rest of the code. I suppose
> > if we could declare variables anywhere we could always keep
> > the two together so it wouldn't look so weird, but can't do
> > that for the time being. And even with that it would still
> > lead to less succinct code, which I generally dislike.
> 
> I'd prefer { } over memset, assuming clang and gcc would treat it
> correctly. Ville, I can submit a patch, unless you want to do it
> yourself as it's a fallout from drm_display_mode shrinkage ;-)
> (seriously speaking, not pushing you, I just want to avoid duplicating
> work).

Go ahead if you want to. I'm in middle of a bigger rebase atm
so can't do it right this minute myself.

-- 
Ville Syrjälä
Intel
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