On Tuesday, December 22nd, 2020 at 2:59 PM, Daniel Vetter <daniel@xxxxxxxx> wrote: > > + * type: > > + * Immutable property describing the type of the plane. > > + * > > + * For user-space which has enabled the &DRM_CLIENT_CAP_UNIVERSAL_PLANES > > s/UNIVERSAL_PLANES/ATOMIC/ here? > > With just universal planes you don't have atomic test-only. But I guess it > also works as-is, I'm just not entirely clear what you want to state here. Right. This paragraph was written when I wasn't aware about ATOMIC implicitly enabling UNIVERSAL_PLANES. Fixed in v5. > > + * capability, the plane type is just a hint and is mostly superseded by > > + * atomic test-only commits. The type hint can still be used to come up > > + * more easily with a plane configuration accepted by the driver. Note that > > + * &DRM_CLIENT_CAP_UNIVERSAL_PLANES is implicitly enabled by > > + * &DRM_CLIENT_CAP_ATOMIC. > > + * > > + * The value of this property can be one of the following: > > + * > > + * "Primary": > > + * To light up a CRTC, attaching a primary plane is the most likely to > > + * work if it covers the whole CRTC and doesn't have scaling or > > + * cropping set up. > > + * > > + * Drivers may support more features for the primary plane, user-space > > + * can find out with test-only atomic commits. > > + * > > + * Primary planes are implicitly used by the kernel in the legacy > > + * IOCTLs &DRM_IOCTL_MODE_SETCRTC and &DRM_IOCTL_MODE_PAGE_FLIP. > > + * Therefore user-space must not mix explicit usage of any primary > > + * plane (e.g. through an atomic commit) with these legacy IOCTLs. > > Empty line here for reading comfort in plain text? Same below. > > Since you mention formats below, I also wonder whether we should state > here that xrgb8888 is generally supported, worst case through software > emulation. That's defacto the uapi we have to adhere to. I wonder. If a new driver decides not to support XRGB8888, that wouldn't be a kernel regression because it's about new hardware. Do we want to formally lock future drivers into XRGB8888 support? Or do we want to open the door for a driver to break this assumption, even if most user-space won't work on the new hardware? I guess all of this is mostly theoretical at this point. _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
