On Tue, Dec 22, 2020 at 02:35:21PM +0100, Simon Ser wrote: > Add a new entry for "type" in the section for standard plane properties. > > v3: improve paragraph about mixing legacy IOCTLs with explicit usage, > not that a driver may support cursors without cursor planes (Daniel) s/not/note/ > > v4: fixing rebase gone wrong > > Signed-off-by: Simon Ser <contact@xxxxxxxxxxx> > Cc: Daniel Vetter <daniel@xxxxxxxx> > Cc: Pekka Paalanen <ppaalanen@xxxxxxxxx> > --- > drivers/gpu/drm/drm_plane.c | 58 ++++++++++++++++++++++++++++++++++--- > 1 file changed, 54 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/drm_plane.c b/drivers/gpu/drm/drm_plane.c > index b15b65e48555..9dce5be5780c 100644 > --- a/drivers/gpu/drm/drm_plane.c > +++ b/drivers/gpu/drm/drm_plane.c > @@ -49,10 +49,8 @@ > * &struct drm_plane (possibly as part of a larger structure) and registers it > * with a call to drm_universal_plane_init(). > * > - * The type of a plane is exposed in the immutable "type" enumeration property, > - * which has one of the following values: "Overlay", "Primary", "Cursor" (see > - * enum drm_plane_type). A plane can be compatible with multiple CRTCs, see > - * &drm_plane.possible_crtcs. > + * Each plane has a type, see enum drm_plane_type. A plane can be compatible > + * with multiple CRTCs, see &drm_plane.possible_crtcs. > * > * Each CRTC must have a unique primary plane userspace can attach to enable > * the CRTC. In other words, userspace must be able to attach a different > @@ -72,6 +70,58 @@ > * > * DRM planes have a few standardized properties: > * > + * 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. > + * capability, the plane type is just a hint and is mostly superseded by 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. > + * "Cursor": > + * To enable this plane, using a framebuffer configured without scaling > + * or cropping and with the following properties is the most likely to > + * work: > + * > + * - If the driver provides the capabilities &DRM_CAP_CURSOR_WIDTH and > + * &DRM_CAP_CURSOR_HEIGHT, create the framebuffer with this size. > + * Otherwise, create a framebuffer with the size 64x64. > + * - If the driver doesn't support modifiers, create a framebuffer with > + * a linear layout. Otherwise, use the IN_FORMATS plane property. > + * > + * Drivers may support more features for the cursor plane, user-space > + * can find out with test-only atomic commits. > + * > + * Cursor planes are implicitly used by the kernel in the legacy > + * IOCTLs &DRM_IOCTL_MODE_CURSOR and &DRM_IOCTL_MODE_CURSOR2. > + * Therefore user-space must not mix explicit usage of any cursor > + * plane (e.g. through an atomic commit) with these legacy IOCTLs. > + * > + * Some drivers may support cursors even if no cursor plane is exposed. > + * In this case, the legacy cursor IOCTLs can be used to configure the > + * cursor. > + * "Overlay": > + * Neither primary nor cursor. > + * > + * Overlay planes are the only planes exposed when the > + * &DRM_CLIENT_CAP_UNIVERSAL_PLANES capability is disabled. > + * Just some thoughts about, feel free to merge as-is. Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx> > * IN_FORMATS: > * Blob property which contains the set of buffer format and modifier > * pairs supported by this plane. The blob is a struct > -- > 2.29.2 > -- 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
