[PATCH] drm/atomic: Add target_vblank support in atomic helpers.
Grodzovsky, Andrey
Andrey.Grodzovsky at amd.com
Wed Jan 4 16:36:50 UTC 2017
> -----Original Message-----
> From: Daniel Vetter [mailto:daniel.vetter at ffwll.ch] On Behalf Of Daniel
> Vetter
> Sent: Wednesday, January 04, 2017 3:44 AM
> To: Grodzovsky, Andrey
> Cc: dri-devel at lists.freedesktop.org; daniel.vetter at ffwll.ch; Deucher,
> Alexander; Daenzer, Michel; Wentland, Harry
> Subject: Re: [PATCH] drm/atomic: Add target_vblank support in atomic
> helpers.
>
> On Tue, Jan 03, 2017 at 10:06:38AM -0500, Andrey Grodzovsky wrote:
> > Allows usage of the new page_flip_target hook for drivers implementing
> > the atomic path.
> > Provides default atomic helper for the new hook.
> >
> > Signed-off-by: Andrey Grodzovsky <Andrey.Grodzovsky at amd.com>
>
> Please keep a per-patch changelog so that it's easier for everyone to follow
> the evolution of this patch.
>
> > ---
> > drivers/gpu/drm/drm_atomic_helper.c | 146
> ++++++++++++++++++++++++++++--------
> > include/drm/drm_atomic_helper.h | 6 ++
> > include/drm/drm_crtc.h | 3 +
> > 3 files changed, 125 insertions(+), 30 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/drm_atomic_helper.c
> > b/drivers/gpu/drm/drm_atomic_helper.c
> > index 583f47f..5e76f90 100644
> > --- a/drivers/gpu/drm/drm_atomic_helper.c
> > +++ b/drivers/gpu/drm/drm_atomic_helper.c
> > @@ -2733,6 +2733,59 @@ int drm_atomic_helper_resume(struct
> drm_device
> > *dev, } EXPORT_SYMBOL(drm_atomic_helper_connector_set_property);
> >
> > +static int drm_atomic_helper_page_flip_create_state(
>
> I'd just call this page_flip_common without the long namespace prefix since
> it's static. And without the create_state name since this function also does
> some basic checks.
>
> > + struct drm_atomic_state *state,
> > + struct drm_crtc *crtc,
> > + struct drm_framebuffer *fb,
> > + struct drm_pending_vblank_event *event) {
> > + struct drm_plane *plane = crtc->primary;
> > + struct drm_plane_state *plane_state;
> > + struct drm_crtc_state *crtc_state;
> > + int ret = 0;
> > +
> > + crtc_state = drm_atomic_get_crtc_state(state, crtc);
> > + if (IS_ERR(crtc_state))
> > + return PTR_ERR(crtc_state);
> > +
> > + crtc_state->event = event;
> > +
> > + plane_state = drm_atomic_get_plane_state(state, plane);
> > + if (IS_ERR(plane_state))
> > + return PTR_ERR(plane_state);
> > +
> > +
> > + ret = drm_atomic_set_crtc_for_plane(plane_state, crtc);
> > + if (ret != 0)
> > + return ret;
> > + drm_atomic_set_fb_for_plane(plane_state, fb);
> > +
> > + /* Make sure we don't accidentally do a full modeset. */
> > + state->allow_modeset = false;
> > + if (!crtc_state->active) {
> > + DRM_DEBUG_ATOMIC("[CRTC:%d] disabled, rejecting legacy
> flip\n",
> > + crtc->base.id);
> > + return -EINVAL;
> > + }
> > +
> > + return ret;
> > +}
> > +
> > +static void drm_atomic_helper_page_flip_prepare_retry(
> > + struct drm_atomic_state *state,
> > + struct drm_plane *plane)
> > +{
> > + drm_atomic_state_clear(state);
> > + drm_atomic_legacy_backoff(state);
> > +
> > + /*
> > + * Someone might have exchanged the framebuffer while we
> dropped locks
> > + * in the backoff code. We need to fix up the fb refcount tracking the
> > + * core does for us.
> > + */
> > + plane->old_fb = plane->fb;
>
> There's a lot more places where we do this trick, please either refactor them
> all, or none. Personally I'd go with none since the function call is more
> verbose than the assignement, and you're hiding this rather important
> comment behind a function name that doesn't say what games are being
> played here.
>
> > +}
> > +
> > /**
> > * drm_atomic_helper_page_flip - execute a legacy page flip
> > * @crtc: DRM crtc
> > @@ -2756,8 +2809,6 @@ int drm_atomic_helper_page_flip(struct drm_crtc
> > *crtc, {
> > struct drm_plane *plane = crtc->primary;
> > struct drm_atomic_state *state;
> > - struct drm_plane_state *plane_state;
> > - struct drm_crtc_state *crtc_state;
> > int ret = 0;
> >
> > if (flags & DRM_MODE_PAGE_FLIP_ASYNC) @@ -2768,35 +2819,79
> @@ int
> > drm_atomic_helper_page_flip(struct drm_crtc *crtc,
> > return -ENOMEM;
> >
> > state->acquire_ctx = drm_modeset_legacy_acquire_ctx(crtc);
> > +
> > retry:
> > - crtc_state = drm_atomic_get_crtc_state(state, crtc);
> > - if (IS_ERR(crtc_state)) {
> > - ret = PTR_ERR(crtc_state);
> > + ret = drm_atomic_helper_page_flip_create_state(state, crtc, fb,
> event);
> > + if (ret != 0)
> > goto fail;
> > - }
> > - crtc_state->event = event;
> >
> > - plane_state = drm_atomic_get_plane_state(state, plane);
> > - if (IS_ERR(plane_state)) {
> > - ret = PTR_ERR(plane_state);
> > - goto fail;
> > - }
> > + ret = drm_atomic_nonblocking_commit(state);
> >
> > - ret = drm_atomic_set_crtc_for_plane(plane_state, crtc);
> > +fail:
> > + if (ret == -EDEADLK)
> > + goto backoff;
> > +
> > + drm_atomic_state_put(state);
> > + return ret;
> > +
> > +backoff:
> > + drm_atomic_helper_page_flip_prepare_retry(state, plane);
> > + goto retry;
> > +}
> > +EXPORT_SYMBOL(drm_atomic_helper_page_flip);
> > +
> > +/**
> > + * drm_atomic_helper_page_flip - execute a legacy page flip
> > + * @crtc: DRM crtc
> > + * @fb: DRM framebuffer
> > + * @event: optional DRM event to signal upon completion
> > + * @flags: flip flags for non-vblank sync'ed updates
> > + *
> > + * Provides a default page flip on specific vblank implementation
> > +using
> > + * the atomic driver interface.
> > + *
> > + * Note that for now so called async page flips (i.e. updates which
> > +are not
> > + * synchronized to vblank) are not supported, since the atomic
> > +interfaces have
> > + * no provisions for this yet.
> > + *
> > + * Returns:
> > + * Returns 0 on success, negative errno numbers on failure.
>
> Kerneldoc isn't updated, just verbatim copypaste. Please also linke these
> 2 functions. And if you have time, would be good to sprinkle links to the
Not sure here, do you mean kerneldoc is not generated for the new helper function ? If so ,
Is it because @tags are missing ?
> vfunc hooks for each of these default helpers (they're unfortunately missing
> ...), e.g. here &drm_crtc_funcs.page_flip_target.
Do you mean adding kernedoc for the vfunc hook ?
Thanks, Andrey
>
> And please build the docs per http://blog.ffwll.ch/2016/12/howto-docs.html
> and make sure it all looks pretty.
>
> > + */
> > +int drm_atomic_helper_page_flip_on_target_vblank(
>
> Please name this helper to match the vhook it's supposed to slot into, i.e.
> drm_atomic_helper_page_flip_target.
>
> > + struct drm_crtc *crtc,
> > + struct drm_framebuffer *fb,
> > + struct drm_pending_vblank_event *event,
> > + uint32_t flags,
> > + uint32_t target)
> > +{
> > + struct drm_plane *plane = crtc->primary;
> > + struct drm_atomic_state *state;
> > + struct drm_crtc_state *crtc_state;
> > + int ret = 0;
> > +
> > + if (flags & DRM_MODE_PAGE_FLIP_ASYNC)
> > + return -EINVAL;
> > +
> > + state = drm_atomic_state_alloc(plane->dev);
> > + if (!state)
> > + return -ENOMEM;
> > +
> > + state->acquire_ctx = drm_modeset_legacy_acquire_ctx(crtc);
> > +
> > +retry:
> > + ret = drm_atomic_helper_page_flip_create_state(state, crtc, fb,
> > +event);
> > if (ret != 0)
> > goto fail;
> > - drm_atomic_set_fb_for_plane(plane_state, fb);
> >
> > - /* Make sure we don't accidentally do a full modeset. */
> > - state->allow_modeset = false;
> > - if (!crtc_state->active) {
> > - DRM_DEBUG_ATOMIC("[CRTC:%d] disabled, rejecting legacy
> flip\n",
> > - crtc->base.id);
> > + crtc_state = drm_atomic_get_existing_crtc_state(state, crtc);
> > + if (WARN_ON(!crtc_state)) {
> > ret = -EINVAL;
> > goto fail;
> > }
> > + crtc_state->target_vblank = target;
> >
> > ret = drm_atomic_nonblocking_commit(state);
> > +
> > fail:
> > if (ret == -EDEADLK)
> > goto backoff;
> > @@ -2805,19 +2900,10 @@ int drm_atomic_helper_page_flip(struct
> drm_crtc *crtc,
> > return ret;
> >
> > backoff:
> > - drm_atomic_state_clear(state);
> > - drm_atomic_legacy_backoff(state);
> > -
> > - /*
> > - * Someone might have exchanged the framebuffer while we
> dropped locks
> > - * in the backoff code. We need to fix up the fb refcount tracking the
> > - * core does for us.
> > - */
> > - plane->old_fb = plane->fb;
> > -
> > + drm_atomic_helper_page_flip_prepare_retry(state, plane);
> > goto retry;
> > }
> > -EXPORT_SYMBOL(drm_atomic_helper_page_flip);
> > +EXPORT_SYMBOL(drm_atomic_helper_page_flip_on_target_vblank);
> >
> > /**
> > * drm_atomic_helper_connector_dpms() - connector dpms helper
> > implementation diff --git a/include/drm/drm_atomic_helper.h
> > b/include/drm/drm_atomic_helper.h index 7ff92b0..e8cb6b7 100644
> > --- a/include/drm/drm_atomic_helper.h
> > +++ b/include/drm/drm_atomic_helper.h
> > @@ -124,6 +124,12 @@ int drm_atomic_helper_page_flip(struct drm_crtc
> *crtc,
> > struct drm_framebuffer *fb,
> > struct drm_pending_vblank_event *event,
> > uint32_t flags);
> > +int drm_atomic_helper_page_flip_on_target_vblank(
> > + struct drm_crtc *crtc,
> > + struct drm_framebuffer *fb,
> > + struct drm_pending_vblank_event *event,
> > + uint32_t flags,
> > + uint32_t target);
> > int drm_atomic_helper_connector_dpms(struct drm_connector
> *connector,
> > int mode);
> > struct drm_encoder *
> > diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h index
> > 946672f..cc926dc 100644
> > --- a/include/drm/drm_crtc.h
> > +++ b/include/drm/drm_crtc.h
> > @@ -103,6 +103,7 @@ static inline uint64_t I642U64(int64_t val)
> > * @ctm: Transformation matrix
> > * @gamma_lut: Lookup table for converting pixel data after the
> > * conversion matrix
> > + * @target_vblank: Target vblank count to flip
> > * @state: backpointer to global drm_atomic_state
> > *
> > * Note that the distinction between @enable and @active is rather
> subtile:
> > @@ -156,6 +157,8 @@ struct drm_crtc_state {
> > struct drm_property_blob *ctm;
> > struct drm_property_blob *gamma_lut;
> >
> > + u32 target_vblank;
>
> The in-line style is preferred for structures, since it allows to group comments
> with each member. There's also still the question of how drivers opt-in into
> target_vblank (only amdgpu, and then only in your private branch supports
> it). I think that should be documented in the kernel-doc.
>
> Thanks, Daniel
> > +
> > /**
> > * @event:
> > *
> > --
> > 1.9.1
> >
>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch
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