On Wed, 2009-12-23 at 22:55 +0100, Luca Tettamanti wrote: > On Wed, Dec 23, 2009 at 10:05 PM, Robert Noland <rnol...@2hip.net> wrote: > > On Wed, 2009-12-23 at 21:36 +0100, Luca Tettamanti wrote: > >> A drm_handle_t can be safely converted to a pointer and back even on a > >> 64bit platform (where the size is not the same). > >> > >> Signed-off-by: Luca Tettamanti <kronos...@gmail.com> > >> --- > >> I looked at the kernel part of the ioctl and it seems that the handle is > >> always a 32bit quantity, but please double check this patch :) > > > > It's size varies with architecture on non-linux. > > Ah, I see. The handle is a long under BSD. > > > This patch shouldn't cause issues, > > Yes, under BSD the cast is superfluous, but harmless. > > > however I would personally really like to see drm_handle_t > > used consistently and correctly. If handle were declared as > > drm_handle_t it would avoid a lot of casting in libdrm and would have > > allowed me to reliably use arbitrary handles for maps on both i386 and > > amd64, by defining drm_handle_t to off_t. As it happens, that requires > > minor touching of some of the DDX drivers though. > > struct drm_map is used as an ioctl argument, so changing the type > there would break the ABI. Furthermore I fear that using a type whose > size changes between i386 and amd64 would result in additional fun in > maintaining the 32 bit compat interface ;-)
I personally vote for just making it an off_t, which is always 64 bits for us. I just had to overhaul all of our mmap stuff and since I still only have 32 bits to work with on i386, I could only steal the upper 4 bits for a globally unique map id, which limits map size to 256MB. On amd64, I stole the upper 24 bits for the map id which still allows any single map to be up to 1TB in size. robert. > Luca -- Robert Noland <rnol...@2hip.net> 2Hip Networks ------------------------------------------------------------------------------ This SF.Net email is sponsored by the Verizon Developer Community Take advantage of Verizon's best-in-class app development support A streamlined, 14 day to market process makes app distribution fast and easy Join now and get one step closer to millions of Verizon customers http://p.sf.net/sfu/verizon-dev2dev -- _______________________________________________ Dri-devel mailing list Dri-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/dri-devel
