On Wed, 2020-04-15 at 13:13 +0200, Daniel Vetter wrote: > 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 Okay, I understand your point. Leaving gma500 without a proper implementation of the "Automatic" value isn't an option though as that would break the whole purpose of this patchset: having a property that works precisely the same way across all drivers. I'll build a patch that implements standards-compliant behavior for gma500 then, so that it can use the same property as the others. Regards Yussuf _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
