From: coypu@sdf.org
To: Daniel Vetter <daniel@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
Subject: Re: [PATCH 2/2] Use char * for struct drm_dp_aux_msg's buffer
Date: Wed, 23 May 2018 10:09:36 +0000 [thread overview]
Message-ID: <20180523100936.GA11820@SDF.ORG> (raw)
In-Reply-To: <20180523090928.GT3438@phenom.ffwll.local>
It's GCC's -Wpointer-arith.
I'm stealing your code for another project that happened to have it on
by default. I'm trying to look for opportunities to contribute back
positive changes :-)
On Wed, May 23, 2018 at 11:09:28AM +0200, Daniel Vetter wrote:
> On Tue, May 22, 2018 at 11:33:35AM +0300, Jani Nikula wrote:
> > On Mon, 21 May 2018, Maya Rashish <coypu@sdf.org> wrote:
> > > In drm_dp_i2c_drain_msg we do msg.buffer += err which isn't
> > > legal for void *.
> >
> > Well, this isn't pedantic C, it's GCC. There are tons of pointer
> > arithmetics for void pointers all over the kernel.
>
> I thought C99 even deprecated char * as the generic pointer, recommending
> void * instead, which guarantees the exact same pointer arithmetic as char
> * (but has the special casting rules).
>
> Which static checker came up with this?
> -Daniel
>
> >
> > BR,
> > Jani.
> >
> > > ---
> > > include/drm/drm_dp_helper.h | 2 +-
> > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
> > > index 62903bae..06f9a61f 100644
> > > --- a/include/drm/drm_dp_helper.h
> > > +++ b/include/drm/drm_dp_helper.h
> > > @@ -1058,7 +1058,7 @@ struct drm_dp_aux_msg {
> > > unsigned int address;
> > > u8 request;
> > > u8 reply;
> > > - void *buffer;
> > > + char *buffer;
> > > size_t size;
> > > };
> >
> > --
> > Jani Nikula, Intel Open Source Graphics Center
> > _______________________________________________
> > dri-devel mailing list
> > dri-devel@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/dri-devel
>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch
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prev parent reply other threads:[~2018-05-23 10:09 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-21 23:36 [PATCH 2/2] Use char * for struct drm_dp_aux_msg's buffer Maya Rashish
2018-05-22 8:33 ` Jani Nikula
2018-05-23 9:09 ` Daniel Vetter
2018-05-23 9:56 ` Jani Nikula
2018-05-24 8:12 ` Daniel Vetter
2018-05-23 10:09 ` coypu [this message]
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