On Sat, Apr 28, 2018 at 7:22 PM, Ilia Mirkin <[email protected]> wrote: > On Thu, Mar 8, 2018 at 11:29 PM, Ilia Mirkin <[email protected]> wrote: >> On Mon, Mar 5, 2018 at 7:33 AM, Ilia Mirkin <[email protected]> wrote: >>> 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! >> >> I just tested this out against xorg 1.19.5. With your patch, I get an >> extremely dark screen. I think it's just getting the first 256 of the >> 1024 values (I checked -- gamma_set is still only getting 256 values). >> So we have to do something a bit cleverer to fix this scenario... >> ideas? > > Mario, > > Have you given this any thought? Is there a way to detect one or the > other scenario? I'd rather not put something in where we check the X > version at compile time. Did the ABI get bumped in 1.20 perhaps? > > -ilia
Nope, haven't had time to retest on 1.19, too much "fun" trying to tame all those new server 1.20 bugs which got in the way of depth 30 stuff. I think the video ABI got bumped in 1.20. -mario _______________________________________________ Nouveau mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/nouveau
