On Mon, Mar 26, 2018 at 10:45 PM, Maxime Ripard <maxime.ripard@xxxxxxxxxxx> wrote: > On Mon, Mar 26, 2018 at 10:22:45PM +0800, Chen-Yu Tsai wrote: >> On Mon, Mar 26, 2018 at 10:14 PM, Joonas Kylmälä <joonas.kylmala@xxxxxx> wrote: >> > Hi DRM subsystem developers, >> > >> > I ran into this patch where overlay plane was switched to cursor plane >> > because there was no proper cursor plane available on the display >> > hardware: <https://lkml.org/lkml/2018/3/17/120>. Can we discuss whether >> > to have a policy of using a normal plane for cursor plane in case a >> > dedicated HW cursor plane is missing? >> > >> > Daniel Vetter suggests that it might be fine to use normal plane for >> > cursor plane because how to use the plane would be only "a hint to >> > userspace" (see the email linked). >> > >> > My motivation for having this discussion is that the newer Allwinner >> > SoCs don't have dedicated HW cursor plane and the sun4i DRM driver >> > currently uses the extra planes as overlay planes which makes moving the >> > cursor on Xfce4 DE a terrible experience. To have better cursor moving >> > experience one overlay plane would need to be sacrificed. >> >> If you look at the development history, we've never supported cursor planes. > > X can use an overlay to put the cursor though. > >> At the beginning we supported one main plane and one overlay plane. That was >> it. The Display Engine 1.0 does have support for an extra hardware cursor, >> but we haven't done the work to support it yet. I don't know about the >> Display Engine 2.0 though. > > An issue with supporting the hardware cursor we have is that as far as > I understood, the cursor plane in DRM has the assumption that it would > be an ARGB format. In the first display engine, the format is actually > an 8-bit palette with 1 bit of alpha iirc. Looks like it's 32x32 pixels with an 8-bit (max) palette, with full RGBA for the colors in the palette. I don't see the 1 bit alpha you mentioned. Looks like this needs some extra work for building the palette and copying the cursor image. ChenYu _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
