On Mon, Mar 5, 2018 at 1:17 AM, Mario Kleiner <[email protected]> wrote: > On 03/03/2018 12:59 AM, Ilia Mirkin wrote: >> >> On Fri, Mar 2, 2018 at 6:46 PM, Mario Kleiner >> <[email protected]> wrote: >>> >>> On 03/02/2018 11:29 PM, Ilia Mirkin wrote: >>>> >>>> OK, so even if you're passing 1024 to xf86HandleColormaps, gamma_set >>>> still only gets called with a 256-entry LUT? If so, that works nicely >>>> here, but is not intuitive :) >>> >>> >>> Yes. Lots of remapping in the server, i get dizzy everytime i look at it, >>> and forget almost immediately how stuff fits together when i don't look >>> at >>> it. Anyway, the final downsampling from 1024 -> 256 hw lut happens in >>> xf86RandR12CrtcComputeGamma(), see >>> >>> >>> https://cgit.freedesktop.org/xorg/xserver/commit/?id=b5f9fcd50a999a00128c0cc3f6e7d1f66182c9d5 >>> >>> for the latest. I'll propose that one to get cherry-picked into the >>> server-1.19 branch as well. >> >> >> Hrmph. That means we should try to adjust the gamma_set helper to do >> the sampling when receiving a 1024-sized LUT, if people will use older >> X servers (seems likely). Should hopefully be straightforward, to >> handle just that one case. > > > I think we never receive anything but a 256 slot LUT via gamma_set afaics? > The server initializes xf86Crtc's gamma_size to 256 at startup, and none of > the ddx'es ever overrides that with actual info from the kernel. > > What happens on older servers without that patch iff color depth 30 is > selected is simply that the gamma table updates no-op, so the server runs > with an identity gamma table setup at startup. Not perfect, but also not > that bad, given that probably most people run their setups with a gamma of > 1.0 anyway. At default depth 24 stuff works as usual.
Ah OK. That's not so bad. I'll try to play around with it this week. Thanks for the explanation! -ilia _______________________________________________ Nouveau mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/nouveau
