On Mon, 9 Mar 2020 21:23:06 +0200 Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> wrote: > On Mon, Mar 09, 2020 at 11:50:59AM +0100, Philipp Zabel wrote: > > On Thu, 2019-11-14 at 14:17 +0100, Marek Vasut wrote: > > > The bus_flags and bus_format handling logic does not seem to cover > > > all potential usecases. Specifically, this seems to fail with an > > > "edt,etm0700g0edh6" display attached to an 24bit display interface, > > > with interface-pix-fmt = "rgb24" set in DT. > > > > interface-pix-fmt is a legacy property that was never intended to be > > used as an override for the panel bus format. The bus flags were > > supposed to be set from the display-timings node, back when there was no > > of-graph connected panel at all. > > > > That being said, there isn't really a proper alternative that allows to > > override the bus format requested by the panel driver in the device tree > > to account for weird wiring. We could reuse the bus-width endpoint > > property documented in [1], but that wouldn't completely specify how the > > RGB components are to be mapped onto the parallel bus. > > > > [1] Documentation/devicetree/bindings/media/video-interfaces.txt > > Things are funny sometimes, I've run into the exact same problem with a > different display controller today. > > Shouldn't we use the data-shift property from [1] to specify this ? > Combined with Boris' bus format negotiation for bridges, I think we > would have all the components in place to solve this problem properly. I wonder if we shouldn't take more complex pin mappings into account now and go directly for a data-mapping property describing those mappings using a string. This way we'd have a single property that would work for both fully parallel buses (DPI/RGB) and serial (or partially parallel) ones (LVDS). _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
