| Message ID | 20201217113220.102271-6-contact@emersion.fr (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/doc: misc documentation improvements | expand |
On Thu, Dec 17, 2020 at 12:32:16PM +0100, Simon Ser wrote: > Add a new entry for "type" in the section for standard plane properties. > > Signed-off-by: Simon Ser <contact@emersion.fr> > Cc: Daniel Vetter <daniel@ffwll.ch> > Cc: Pekka Paalanen <ppaalanen@gmail.com> > --- > drivers/gpu/drm/drm_plane.c | 52 ++++++++++++++++++++++++++++++++++--- > 1 file changed, 48 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/drm_plane.c b/drivers/gpu/drm/drm_plane.c > index 4a66374dc355..fef63bb7d293 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. > * > * Legacy uAPI doesn't expose the primary and cursor planes directly. DRM core > * relies on the driver to set the primary and optionally the cursor plane used > @@ -66,6 +64,52 @@ > * > * 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 > + * capability, the plane type is just a hint and is mostly superseded by 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. > + * > + * User-space must not mix the legacy IOCTLs &DRM_IOCTL_MODE_SETCRTC or > + * &DRM_IOCTL_MODE_PAGE_FLIP with atomic commits involving a primary s/a primary/any primary/ to make it a bit stronger > + * plane. You can also use primary planes through the setplane ioctl. Also this doesn't explain why, which is maybe a bit head scratching. I'd put something like "Primary planes are used implicitly by the kernel in the legacy IOCTLs SETCRTC & FLIP. Therefore userspace must not mix explicit usage of any primary plane (e.g. through ATOMIC IOCTL) with these legacy IOCTL." Feel free to bikeshed further. > + * "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. > + * > + * User-space must not mix the legacy IOCTLs &DRM_IOCTL_MODE_CURSOR or > + * &DRM_IOCTL_MODE_CURSOR2 with atomic commits involving a cursor > + * plane. Same here. Maybe we should also note that cursors are not necessarily exposed as cursor planes, even for drivers supporting atomic modeset. -Daniel > + * "Overlay": > + * Neither primary nor cursor. > + * > + * Overlay planes are the only planes exposed when the > + * &DRM_CLIENT_CAP_UNIVERSAL_PLANES capability is disabled. > + * > * 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 >
diff --git a/drivers/gpu/drm/drm_plane.c b/drivers/gpu/drm/drm_plane.c index 4a66374dc355..fef63bb7d293 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. * * Legacy uAPI doesn't expose the primary and cursor planes directly. DRM core * relies on the driver to set the primary and optionally the cursor plane used @@ -66,6 +64,52 @@ * * 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 + * 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. + * + * User-space must not mix the legacy IOCTLs &DRM_IOCTL_MODE_SETCRTC or + * &DRM_IOCTL_MODE_PAGE_FLIP with atomic commits involving a primary + * plane. + * "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. + * + * User-space must not mix the legacy IOCTLs &DRM_IOCTL_MODE_CURSOR or + * &DRM_IOCTL_MODE_CURSOR2 with atomic commits involving a cursor + * plane. + * "Overlay": + * Neither primary nor cursor. + * + * Overlay planes are the only planes exposed when the + * &DRM_CLIENT_CAP_UNIVERSAL_PLANES capability is disabled. + * * IN_FORMATS: * Blob property which contains the set of buffer format and modifier * pairs supported by this plane. The blob is a struct
Add a new entry for "type" in the section for standard plane properties. Signed-off-by: Simon Ser <contact@emersion.fr> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Pekka Paalanen <ppaalanen@gmail.com> --- drivers/gpu/drm/drm_plane.c | 52 ++++++++++++++++++++++++++++++++++--- 1 file changed, 48 insertions(+), 4 deletions(-)