On Wed, May 23, 2018 at 12:56:25PM +0300, Jani Nikula wrote: > On Wed, 23 May 2018, Daniel Vetter <daniel@xxxxxxxx> wrote: > > On Tue, May 22, 2018 at 11:33:35AM +0300, Jani Nikula wrote: > >> On Mon, 21 May 2018, Maya Rashish <coypu@xxxxxxx> 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. > > > > TTBOMK, > > > I thought C99 even deprecated char * as the generic pointer, recommending > > void * instead, > > True. > > > which guarantees the exact same pointer arithmetic as char * > > False. Indeed: https://stackoverflow.com/questions/3523145/pointer-arithmetic-for-void-pointer-in-c TIL > > (but has the special casting rules). > > True. > > Void pointer arithmetics is still just a GCC extension, also supported > by Clang for compatibility. > > > Which static checker came up with this? > > Should be enough to turn GCC warning knobs to 11. But I don't imagine > being able to change this in the kernel code base. Yeah, I think kernel is so full of gccism that this won't work. I think we'll just leave this as-is. Especially since the stackoverflow answer suggests I'm by far not the only one who got tricked by the standard's wording. -Daniel > > BR, > Jani. > > > -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@xxxxxxxxxxxxxxxxxxxxx > >> https://lists.freedesktop.org/mailman/listinfo/dri-devel > > -- > Jani Nikula, Intel Open Source Graphics Center -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
