On Mon, Sep 14, 2020 at 02:13:09AM -0400, Alex Deucher wrote: > On Thu, Sep 10, 2020 at 4:29 AM Simon Ser <contact@xxxxxxxxxxx> wrote: > > > > On Thursday, September 10, 2020 10:18 AM, Daniel Vetter <daniel@xxxxxxxx> wrote: > > > > > On Thu, Sep 10, 2020 at 07:50:59AM +0000, Simon Ser wrote: > > > > > > > On Wednesday, September 9, 2020 12:57 PM, Laurentiu Palcu laurentiu.palcu@xxxxxxxxxxx wrote: > > > > > > > > > Hi all, > > > > > I was wondering whether you could give me an advise on how to proceed further > > > > > with the following issue as I'm preparing to upstream the next set of patches > > > > > for the iMX8MQ display controller(DCSS). The display controller has 3 planes, > > > > > each with 2 CSCs and one degamma LUT. The CSCs are in front and after the LUT > > > > > respectively. Then the output from those 3 pipes is blended together and then > > > > > gamma correction is applied using a linear-to-nonlinear LUT and another CSC, if > > > > > needed. > > > > > Currently, downstream, we have all those CSCs and LUTs hard-coded into a header > > > > > file. Based on the colorspace, range, gamut selected for the output and/or > > > > > plane input, we pick up the right CSCs and LUTs from that header file to > > > > > configure our pipes... I guess this solution does the job, userspace doesn't > > > > > need to care much about how to generate those tables. But, it's also not very > > > > > flexible in case there is an app smart enough to know and actually generate > > > > > their own custom tables. :/ > > > > > Looking through the dri-devel archives, I've seen that there was a tentative to > > > > > implement a more or less generic per-plane LUT/CSC solution but it didn't make > > > > > it in due to lack of userspace consumers... > > > > > > > > Apart from full color management mentioned by Pekka, are there other > > > > use-cases for these per-plane props? > > > > One thing I can think of is that some drivers annoyingly only apply the > > > > per-CRTC gamma LUT to the primary plane. I think it would make more > > > > sense to not attach a gamma prop to the CRTC and instead only attach it > > > > to the primary plane to make that clear. But I guess that would also > > > > break existing user-space? > > > > > > Uh, which drivers? This would be a driver bug (and there's been plenty of > > > those where the cursor has the wrong color temp and fun stuff like that). > > > We need to fix these driver issues instead of lamenting in userspace that > > > it's all kinda broken :-) > > > > Apparently this is bug with the old radeon driver [1]. It works fine on > > all i915 setups I've tried, and also works fine on amdgpu (with DC). > > > > I've opened a radeon bug. > > > > [1]: https://github.com/swaywm/wlroots/issues/968 > > This is a hardware limitation. I suspend all hardware of a certain > age had this same limitation. Old stuff didn't have multiple planes. That doesn't sound right to me. mach64 vt/gt and rage128 had an overlay plane already. I even vaguely remeber staring at some radeon overlay code at some point thinking "that stuff looks identical to the rage128 stuff, wonder why it's not shared code?". > It had a primary plane and a cursor and gamma didn't apply to the > cursor. That last part I can believe. -- Ville Syrjälä Intel _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
