From e954f77f6330028ced7bac4ad22ea69ed64e5725 Mon Sep 17 00:00:00 2001 From: Simon Ser Date: Thu, 21 May 2020 11:09:31 +0000 Subject: [PATCH] drm: add docs for standard CRTC properties MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This patch adds docs for the ACTIVE and MODE_ID CRTC properties. Signed-off-by: Simon Ser Cc: Daniel Vetter Cc: Ville Syrjala Cc: Pekka Paalanen Cc: Michel Dänzer Cc: Daniel Stone Reviewed-by: Pekka Paalanen Reviewed-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/k52vYFBQ5ZO18TgZl3W8MgP6f4qu5Ncir7w-On8Dm0V2KTAcVkUoS7-IGPcvDJAXLsyJAUsD0QFJts3Dy0yWyHXVh85axrZkybh3MGGFhQc=@emersion.fr --- 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..f1216088f65f 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.