On Wed, Apr 15, 2020 at 10:33:25AM +0300, Jani Nikula wrote: > On Tue, 14 Apr 2020, Yussuf Khalil <dev@xxxxxxxxxx> wrote: > > On Tue, 2020-04-14 at 14:34 +0200, Daniel Vetter wrote: > >> On Tue, Apr 14, 2020 at 02:21:06PM +0300, Jani Nikula wrote: > >> > On Tue, 14 Apr 2020, Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx> > >> > wrote: > >> > > On Mon, 13 Apr 2020, Simon Ser <contact@xxxxxxxxxxx> wrote: > >> > > > On Monday, April 13, 2020 11:40 PM, Yussuf Khalil < > >> > > > dev@xxxxxxxxxx> wrote: > >> > > > > >> > > > > DRM now has a globally available "RGB quantization range" > >> > > > > connector > >> > > > > property. i915's "Broadcast RGB" that fulfils the same > >> > > > > purpose is now > >> > > > > considered deprecated, so drop it in favor of the DRM > >> > > > > property. > >> > > > > >> > > > For a UAPI point-of-view, I'm not sure this is fine. Some user- > >> > > > space > >> > > > might depend on this property, dropping it would break such > >> > > > user-space. > >> > > > >> > > Agreed. > >> > > > >> > > > Can we make this property deprecated but still keep it for > >> > > > backwards > >> > > > compatibility? > >> > > > >> > > Would be nice to make the i915 specific property an "alias" for > >> > > the new > >> > > property, however I'm not sure how you'd make that happen. > >> > > Otherwise > >> > > juggling between the two properties is going to be a nightmare. > >> > > >> > Ah, the obvious easy choice is to use the property and enum names > >> > already being used by i915 and gma500, and you have no problem. > >> > Perhaps > >> > they're not the names you'd like, but then looking at the total > >> > lack of > >> > consistency across property naming makes them fit right in. ;) > >> > >> Yeah if we don't have contradictory usage across drivers when > >> modernizing > >> these properties, then let's just stick with the names already there. > >> It's > >> not pretty, but works better since more userspace/internet howtos > >> know how > >> to use this stuff. > >> -Daniel > > > > Note that i915's "Broadcast RGB" isn't the same as gma500's: i915 has an > > "Automatic" option, whereas gma500 does not. > > Adding "Automatic" option that just defaults to "Full" in gma500 does > not break existing userspace, but allows for extending it to do more > clever things later. gma500 could keep it's own property, without the "Automatic" value. We've done tricks like this for other properties too. > > Also, radeon has a property called > > "output_csc" that fulfills a similar purpose. Looking at the code, though, it > > seems that radeon does not adhere to the standard correctly (or I am missing > > something). > > > > An alternative would be to leave the existing driver-specific properties and > > change them to be pseudo-aliases for the "RGB quantization range" property. > > This can be done by letting the drivers read from and write to the new property > > when user-space tries to read or modify the driver's property. This way we could > > retain full backwards compatibility for all drivers equally. > > > > What do you think? > > I'm obviously biased and predisposed to avoid adding extra complexity to > i915 when it's not necessary. We'd have *two* connector properties for > the same thing until the end of time, even if one is an alias for the > other. Yeah just pick one, and implement the others as aliases. Drivers can do the aliases in their atomic_get/set_property functions pretty easily, atomic properties aren't stored anywhere else than decoded (which was done partially to make stuff like this work). Coming up a new property name just so that everyone suffers equally feels silly. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
