On Thu, 21 May 2020 11:09:31 +0000 Simon Ser <contact@xxxxxxxxxxx> wrote: > This patch adds docs for the ACTIVE and MODE_ID CRTC properties. > > Signed-off-by: Simon Ser <contact@xxxxxxxxxxx> > Cc: Daniel Vetter <daniel.vetter@xxxxxxxxx> > Cc: Ville Syrjala <ville.syrjala@xxxxxxxxxxxxxxx> > Cc: Pekka Paalanen <pekka.paalanen@xxxxxxxxxxxxxxx> > Cc: Michel Dänzer <michel@xxxxxxxxxxx> > Cc: Daniel Stone <daniel@xxxxxxxxxxxxx> > --- > > Thanks for the review Daniel! I rejiggered your suggestions a little to > move some ACTIVE bits into the ACTIVE description. > > Documentation/gpu/drm-kms.rst | 6 ++++++ > drivers/gpu/drm/drm_crtc.c | 27 +++++++++++++++++++++++++++ > 2 files changed, 33 insertions(+) > > diff --git a/Documentation/gpu/drm-kms.rst b/Documentation/gpu/drm-kms.rst > index 397314d08f77..975cfeb8a353 100644 > --- a/Documentation/gpu/drm-kms.rst > +++ b/Documentation/gpu/drm-kms.rst > @@ -460,6 +460,12 @@ HDMI Specific Connector Properties > .. kernel-doc:: drivers/gpu/drm/drm_connector.c > :doc: HDMI connector properties > > +Standard CRTC Properties > +------------------------ > + > +.. kernel-doc:: drivers/gpu/drm/drm_crtc.c > + :doc: standard CRTC properties > + > Plane Composition Properties > ---------------------------- > > diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c > index 4936e1080e41..fafb8d3c3235 100644 > --- a/drivers/gpu/drm/drm_crtc.c > +++ b/drivers/gpu/drm/drm_crtc.c > @@ -204,6 +204,33 @@ struct dma_fence *drm_crtc_create_fence(struct drm_crtc *crtc) > return fence; > } > > +/** > + * DOC: standard CRTC properties > + * > + * DRM CRTCs have a few standardized properties: > + * > + * ACTIVE: > + * Atomic property for setting the power state of the CRTC. When set to 1 the > + * CRTC will actively display content. When set to 0 the CRTC will be powered > + * off. There is no expectation that user-space will reset CRTC resources like > + * the mode and planes when setting ACTIVE to 0. > + * > + * User-space can rely on an ACTIVE change to 1 to never fail an atomic test > + * as long as no other property has changed. If a change to ACTIVE fails an > + * atomic test, this is a driver bug. For this reason setting ACTIVE to 0 must > + * not release internal resources (like reserved memory bandwidth or clock > + * generators). > + * > + * Note that the legacy DPMS property on connectors is internally routed to > + * control this property for atomic drivers. > + * MODE_ID: > + * Atomic property for setting the CRTC display timings. The value is the ID > + * of a blob containing the DRM mode info. To disable the CRTC, user-space > + * must set this property to 0. > + * > + * Setting MODE_ID to 0 will release reserved resources for the CRTC. > + */ > + > /** > * drm_crtc_init_with_planes - Initialise a new CRTC object with > * specified primary and cursor planes. Really nice. Reviewed-by: Pekka Paalanen <pekka.paalanen@xxxxxxxxxxxxx> And the patch 1/2 R-b as well. FWIW, as I cannot really check the kernel code is like this, but it totally makes sense from userspace side. I didn't even know these little details before. Thanks, pq
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