On Thu, Nov 6, 2014 at 3:00 PM, Daniel Vetter <daniel.vetter at ffwll.ch> wrote:
> In all cases the text requires that new drivers are converted to the
> atomic interfaces.
>
> v2: Add overview for state handling.
>
> v3: Review from Sean: Some spelling fixes and drop the misguided
> hunk to remove rgba8888 from the plane helpers compat list.
>
> Cc: Sean Paul <seanpaul at chromium.org>
> Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
Reviewed-by: Sean Paul <seanpaul at chromium.org>
> ---
> Documentation/DocBook/drm.tmpl | 20 +++++++++++++++++++-
> drivers/gpu/drm/drm_atomic_helper.c | 36 ++++++++++++++++++++++++++++++++++++
> drivers/gpu/drm/drm_crtc_helper.c | 20 ++++++++++++++++++++
> drivers/gpu/drm/drm_plane_helper.c | 26 ++++++++++++++++++++++++++
> 4 files changed, 101 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/DocBook/drm.tmpl b/Documentation/DocBook/drm.tmpl
> index 748513b34025..f276c2cf806b 100644
> --- a/Documentation/DocBook/drm.tmpl
> +++ b/Documentation/DocBook/drm.tmpl
> @@ -2324,8 +2324,25 @@ void intel_crt_init(struct drm_device *dev)
> </itemizedlist>
> </sect2>
> <sect2>
> + <title>Atomic Modeset Helper Functions Reference</title>
> + <sect3>
> + <title>Overview</title>
> +!Pdrivers/gpu/drm/drm_atomic_helper.c overview
> + </sect3>
> + <sect3>
> + <title>Implementing Asynchronous Atomic Commit</title>
> +!Pdrivers/gpu/drm/drm_atomic_helper.c implementing async commit
> + </sect3>
> + <sect3>
> + <title>Atomic State Reset and Initialization</title>
> +!Pdrivers/gpu/drm/drm_atomic_helper.c atomic state reset and initialization
> + </sect3>
> +!Edrivers/gpu/drm/drm_atomic_helper.c
> + </sect2>
> + <sect2>
> <title>Modeset Helper Functions Reference</title>
> !Edrivers/gpu/drm/drm_crtc_helper.c
> +!Pdrivers/gpu/drm/drm_crtc_helper.c overview
> </sect2>
> <sect2>
> <title>Output Probing Helper Functions Reference</title>
> @@ -2379,7 +2396,8 @@ void intel_crt_init(struct drm_device *dev)
> </sect2>
> <sect2>
> <title id="drm-kms-planehelpers">Plane Helper Reference</title>
> -!Edrivers/gpu/drm/drm_plane_helper.c Plane Helpers
> +!Edrivers/gpu/drm/drm_plane_helper.c
> +!Pdrivers/gpu/drm/drm_plane_helper.c overview
> </sect2>
> </sect1>
>
> diff --git a/drivers/gpu/drm/drm_atomic_helper.c
> b/drivers/gpu/drm/drm_atomic_helper.c
> index 2c38bda217ec..2b1db0c12fdc 100644
> --- a/drivers/gpu/drm/drm_atomic_helper.c
> +++ b/drivers/gpu/drm/drm_atomic_helper.c
> @@ -32,6 +32,27 @@
> #include <drm/drm_atomic_helper.h>
> #include <linux/fence.h>
>
> +/**
> + * DOC: overview
> + *
> + * This helper library provides implementations of check and commit
> functions on
> + * top of the CRTC modeset helper callbacks and the plane helper callbacks.
> It
> + * also provides convenience implementations for the atomic state handling
> + * callbacks for drivers which don't need to subclass the drm core
> structures to
> + * add their own additional internal state.
> + *
> + * This library also provides default implementations for the check callback
> in
> + * drm_atomic_helper_check and for the commit callback with
> + * drm_atomic_helper_commit. But the individual stages and callbacks are
> expose
> + * to allow drivers to mix and match and e.g. use the plane helpers only
> + * together with a driver private modeset implementation.
> + *
> + * This library also provides implementations for all the legacy driver
> + * interfaces on top of the atomic interface. See
> drm_atomic_helper_set_config,
> + * drm_atomic_helper_disable_plane, drm_atomic_helper_disable_plane and the
> + * various functions to implement set_property callbacks. New drivers must
> not
> + * implement these functions themselves but must use the provided helpers.
> + */
> static void
> drm_atomic_helper_plane_changed(struct drm_atomic_state *state,
> struct drm_plane_state *plane_state,
> @@ -1708,6 +1729,21 @@ backoff:
> EXPORT_SYMBOL(drm_atomic_helper_page_flip);
>
> /**
> + * DOC: atomic state reset and initialization
> + *
> + * Both the drm core and the atomic helpers assume that there is always the
> full
> + * and correct atomic software state for all connectors, CRTCs and planes
> + * available. Which is a bit a problem on driver load and also after system
> + * suspend. One way to solve this is to have a hardware state read-out
> + * infrastructure which reconstructs the full software state (e.g. the i915
> + * driver).
> + *
> + * The simpler solution is to just reset the software state to everything
> off,
> + * which is easiest to do by calling drm_mode_config_reset(). To facilitate
> this
> + * the atomic helpers provide default reset implementations for all hooks.
> + */
> +
> +/**
> * drm_atomic_helper_crtc_reset - default ->reset hook for CRTCs
> * @crtc: drm CRTC
> *
> diff --git a/drivers/gpu/drm/drm_crtc_helper.c
> b/drivers/gpu/drm/drm_crtc_helper.c
> index 46728a8ac622..33195e9adaab 100644
> --- a/drivers/gpu/drm/drm_crtc_helper.c
> +++ b/drivers/gpu/drm/drm_crtc_helper.c
> @@ -41,6 +41,26 @@
> #include <drm/drm_plane_helper.h>
> #include <drm/drm_edid.h>
>
> +/**
> + * DOC: overview
> + *
> + * The CRTC modeset helper library provides a default set_config
> implementation
> + * in drm_crtc_helper_set_config(). Plus a few other convenience functions
> using
> + * the same callbacks which drivers can use to e.g. restore the modeset
> + * configuration on resume with drm_helper_resume_force_mode().
> + *
> + * The driver callbacks are mostly compatible with the atomic modeset
> helpers,
> + * except for the handling of the primary plane: Atomic helpers require that
> the
> + * primary plane is implemented as a real standalone plane and not directly
> tied
> + * to the CRTC state. For easier transition this library provides functions
> to
> + * implement the old semantics required by the CRTC helpers using the new
> plane
> + * and atomic helper callbacks.
> + *
> + * Drivers are strongly urged to convert to the atomic helpers (by way of
> first
> + * converting to the plane helpers). New drivers must not use these functions
> + * but need to implement the atomic interface instead, potentially using the
> + * atomic helpers for that.
> + */
> MODULE_AUTHOR("David Airlie, Jesse Barnes");
> MODULE_DESCRIPTION("DRM KMS helper");
> MODULE_LICENSE("GPL and additional rights");
> diff --git a/drivers/gpu/drm/drm_plane_helper.c
> b/drivers/gpu/drm/drm_plane_helper.c
> index a5a295872fbb..fa56bb5da6c3 100644
> --- a/drivers/gpu/drm/drm_plane_helper.c
> +++ b/drivers/gpu/drm/drm_plane_helper.c
> @@ -31,6 +31,32 @@
>
> #define SUBPIXEL_MASK 0xffff
>
> +/**
> + * DOC: overview
> + *
> + * This helper library has two parts. The first part has support to implement
> + * primary plane support on top of the normal CRTC configuration interface.
> + * Since the legacy ->set_config interface ties the primary plane together
> with
> + * the CRTC state this does not allow userspace to disable the primary plane
> + * itself. To avoid too much duplicated code use
> + * drm_plane_helper_check_update() which can be used to enforce the same
> + * restrictions as primary planes had thus. The default primary plane only
> + * expose XRBG8888 and ARGB8888 as valid pixel formats for the attached
> + * framebuffer.
> + *
> + * Drivers are highly recommended to implement proper support for primary
> + * planes, and newly merged drivers must not rely upon these transitional
> + * helpers.
> + *
> + * The second part also implements transitional helpers which allow drivers
> to
> + * gradually switch to the atomic helper infrastructure for plane updates.
> Once
> + * that switch is complete drivers shouldn't use these any longer, instead
> using
> + * the proper legacy implementations for update and disable plane hooks
> provided
> + * by the atomic helpers.
> + *
> + * Again drivers are strongly urged to switch to the new interfaces.
> + */
> +
> /*
> * This is the minimal list of formats that seem to be safe for modeset use
> * with all current DRM drivers. Most hardware can actually support more
> --
> 2.1.1
>
