On Fri, Feb 17, 2017 at 02:42:26PM +0000, Lionel Landwerlin wrote: > On 17/02/17 13:54, Brian Starkey wrote: > > What's the verdict? We've got [1] which is about to become another > > (driver) implementation - better to change before that merges than > > after I guess. > > > > -Brian > > > > [1] https://lkml.org/lkml/2017/2/13/304 > > > > On Wed, Feb 15, 2017 at 11:56:55AM +0000, Daniel Stone wrote: > >> Hi, > >> > >> On 15 February 2017 at 11:39, Ville Syrjälä > >> <ville.syrjala@xxxxxxxxxxxxxxx> wrote: > >>> On Tue, Jan 31, 2017 at 06:46:39PM +0100, Daniel Vetter wrote: > >>>> On Tue, Jan 31, 2017 at 6:22 PM, Ville Syrjälä > >>>> <ville.syrjala@xxxxxxxxxxxxxxx> wrote: > >>>> > Hmm. Two's complement is what I was thinking it is. Which shows that > >>>> > I never managed to read the code in any detail. Definitely needs to > >>>> > be documented properly. > >>>> > >>>> That sounds supremely backwards. I guess we can't fix this anymore? > >>> > >>> I have no idea. Anyone else? > >> > >> I don't know of any implementation using this; maybe closed Intel > >> Android stuff? Certainly GitHub showed no-one using it, and neither X > >> nor Weston/Mutter are using it yet. > >> > >> Cheers, > >> Daniel > > > If we're talking fixed point reprsentation, ChromeOS is using this : > > https://cs.chromium.org/chromium/src/ui/ozone/platform/drm/gpu/drm_device.cc?q=DrmDevice&l=209 So it's already using the sign+magnitude stuff. Which presumably means we can't change it to two's complement anymore :( Maybe we add a CTM2 property ;) Using sign+magnitude definitely looks rather inefficient since there's a branch inside the loop. With two's complement you wouldn't need that thing slowing you down. -- Ville Syrjälä Intel OTC _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
