From 1ea0c02e7018fdefbfc4333c733ce27c2bb70eff Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Mon, 21 Nov 2016 18:18:02 +0100 Subject: [PATCH] drm/atomic: Unconfuse the old_state mess in commmit_tail I totally butcherd the job on typing the kernel-doc for these, and no one realized. Noticed by Russell. Maarten has a more complete approach to this confusion, by making it more explicit what the new/old state is, instead of this magic switching behaviour. v2: - Liviu pointed out that wait_for_fences is even more magic. Leave that as @state, and document @pre_swap better. - While at it, patch in header for the reference section. - Fix spelling issues Russell noticed. v3: Fix up the @pre_swap note (Liviu): Also s/synchronous/blocking/, since async flip is something else than non-blocking. Cc: Liviu Dudau Reported-by: Russell King - ARM Linux Cc: Russell King - ARM Linux Fixes: 9f2a7950e77a ("drm/atomic-helper: nonblocking commit support") Cc: Gustavo Padovan Cc: Maarten Lankhorst Cc: Tomeu Vizoso Cc: Daniel Stone Reviewed-by: Liviu Dudau Signed-off-by: Daniel Vetter Link: http://patchwork.freedesktop.org/patch/msgid/20161121171802.24147-1-daniel.vetter@ffwll.ch --- Documentation/gpu/drm-kms-helpers.rst | 3 + drivers/gpu/drm/drm_atomic_helper.c | 78 +++++++++++++----------- include/drm/drm_modeset_helper_vtables.h | 12 ++-- 3 files changed, 54 insertions(+), 39 deletions(-) diff --git a/Documentation/gpu/drm-kms-helpers.rst b/Documentation/gpu/drm-kms-helpers.rst index 4ca77f675967..03040aa14fe8 100644 --- a/Documentation/gpu/drm-kms-helpers.rst +++ b/Documentation/gpu/drm-kms-helpers.rst @@ -63,6 +63,9 @@ Atomic State Reset and Initialization .. kernel-doc:: drivers/gpu/drm/drm_atomic_helper.c :doc: atomic state reset and initialization +Helper Functions Reference +-------------------------- + .. kernel-doc:: include/drm/drm_atomic_helper.h :internal: diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c index 0b16587cdc62..494680c9056e 100644 --- a/drivers/gpu/drm/drm_atomic_helper.c +++ b/drivers/gpu/drm/drm_atomic_helper.c @@ -1006,13 +1006,21 @@ EXPORT_SYMBOL(drm_atomic_helper_commit_modeset_enables); * drm_atomic_helper_wait_for_fences - wait for fences stashed in plane state * @dev: DRM device * @state: atomic state object with old state structures - * @pre_swap: if true, do an interruptible wait + * @pre_swap: If true, do an interruptible wait, and @state is the new state. + * Otherwise @state is the old state. * * For implicit sync, driver should fish the exclusive fence out from the * incoming fb's and stash it in the drm_plane_state. This is called after * drm_atomic_helper_swap_state() so it uses the current plane state (and * just uses the atomic state to find the changed planes) * + * Note that @pre_swap is needed since the point where we block for fences moves + * around depending upon whether an atomic commit is blocking or + * non-blocking. For async commit all waiting needs to happen after + * drm_atomic_helper_swap_state() is called, but for synchronous commits we want + * to wait **before** we do anything that can't be easily rolled back. That is + * before we call drm_atomic_helper_swap_state(). + * * Returns zero if success or < 0 if dma_fence_wait() fails. */ int drm_atomic_helper_wait_for_fences(struct drm_device *dev, @@ -1147,7 +1155,7 @@ EXPORT_SYMBOL(drm_atomic_helper_wait_for_vblanks); /** * drm_atomic_helper_commit_tail - commit atomic update to hardware - * @state: new modeset state to be committed + * @old_state: atomic state object with old state structures * * This is the default implemenation for the ->atomic_commit_tail() hook of the * &drm_mode_config_helper_funcs vtable. @@ -1158,53 +1166,53 @@ EXPORT_SYMBOL(drm_atomic_helper_wait_for_vblanks); * * For drivers supporting runtime PM the recommended sequence is instead :: * - * drm_atomic_helper_commit_modeset_disables(dev, state); + * drm_atomic_helper_commit_modeset_disables(dev, old_state); * - * drm_atomic_helper_commit_modeset_enables(dev, state); + * drm_atomic_helper_commit_modeset_enables(dev, old_state); * - * drm_atomic_helper_commit_planes(dev, state, + * drm_atomic_helper_commit_planes(dev, old_state, * DRM_PLANE_COMMIT_ACTIVE_ONLY); * * for committing the atomic update to hardware. See the kerneldoc entries for * these three functions for more details. */ -void drm_atomic_helper_commit_tail(struct drm_atomic_state *state) +void drm_atomic_helper_commit_tail(struct drm_atomic_state *old_state) { - struct drm_device *dev = state->dev; + struct drm_device *dev = old_state->dev; - drm_atomic_helper_commit_modeset_disables(dev, state); + drm_atomic_helper_commit_modeset_disables(dev, old_state); - drm_atomic_helper_commit_planes(dev, state, 0); + drm_atomic_helper_commit_planes(dev, old_state, 0); - drm_atomic_helper_commit_modeset_enables(dev, state); + drm_atomic_helper_commit_modeset_enables(dev, old_state); - drm_atomic_helper_commit_hw_done(state); + drm_atomic_helper_commit_hw_done(old_state); - drm_atomic_helper_wait_for_vblanks(dev, state); + drm_atomic_helper_wait_for_vblanks(dev, old_state); - drm_atomic_helper_cleanup_planes(dev, state); + drm_atomic_helper_cleanup_planes(dev, old_state); } EXPORT_SYMBOL(drm_atomic_helper_commit_tail); -static void commit_tail(struct drm_atomic_state *state) +static void commit_tail(struct drm_atomic_state *old_state) { - struct drm_device *dev = state->dev; + struct drm_device *dev = old_state->dev; struct drm_mode_config_helper_funcs *funcs; funcs = dev->mode_config.helper_private; - drm_atomic_helper_wait_for_fences(dev, state, false); + drm_atomic_helper_wait_for_fences(dev, old_state, false); - drm_atomic_helper_wait_for_dependencies(state); + drm_atomic_helper_wait_for_dependencies(old_state); if (funcs && funcs->atomic_commit_tail) - funcs->atomic_commit_tail(state); + funcs->atomic_commit_tail(old_state); else - drm_atomic_helper_commit_tail(state); + drm_atomic_helper_commit_tail(old_state); - drm_atomic_helper_commit_cleanup_done(state); + drm_atomic_helper_commit_cleanup_done(old_state); - drm_atomic_state_put(state); + drm_atomic_state_put(old_state); } static void commit_work(struct work_struct *work) @@ -1498,10 +1506,10 @@ static struct drm_crtc_commit *preceeding_commit(struct drm_crtc *crtc) /** * drm_atomic_helper_wait_for_dependencies - wait for required preceeding commits - * @state: new modeset state to be committed + * @old_state: atomic state object with old state structures * * This function waits for all preceeding commits that touch the same CRTC as - * @state to both be committed to the hardware (as signalled by + * @old_state to both be committed to the hardware (as signalled by * drm_atomic_helper_commit_hw_done) and executed by the hardware (as signalled * by calling drm_crtc_vblank_send_event on the event member of * &drm_crtc_state). @@ -1509,7 +1517,7 @@ static struct drm_crtc_commit *preceeding_commit(struct drm_crtc *crtc) * This is part of the atomic helper support for nonblocking commits, see * drm_atomic_helper_setup_commit() for an overview. */ -void drm_atomic_helper_wait_for_dependencies(struct drm_atomic_state *state) +void drm_atomic_helper_wait_for_dependencies(struct drm_atomic_state *old_state) { struct drm_crtc *crtc; struct drm_crtc_state *crtc_state; @@ -1517,7 +1525,7 @@ void drm_atomic_helper_wait_for_dependencies(struct drm_atomic_state *state) int i; long ret; - for_each_crtc_in_state(state, crtc, crtc_state, i) { + for_each_crtc_in_state(old_state, crtc, crtc_state, i) { spin_lock(&crtc->commit_lock); commit = preceeding_commit(crtc); if (commit) @@ -1548,7 +1556,7 @@ EXPORT_SYMBOL(drm_atomic_helper_wait_for_dependencies); /** * drm_atomic_helper_commit_hw_done - setup possible nonblocking commit - * @state: new modeset state to be committed + * @old_state: atomic state object with old state structures * * This function is used to signal completion of the hardware commit step. After * this step the driver is not allowed to read or change any permanent software @@ -1561,15 +1569,15 @@ EXPORT_SYMBOL(drm_atomic_helper_wait_for_dependencies); * This is part of the atomic helper support for nonblocking commits, see * drm_atomic_helper_setup_commit() for an overview. */ -void drm_atomic_helper_commit_hw_done(struct drm_atomic_state *state) +void drm_atomic_helper_commit_hw_done(struct drm_atomic_state *old_state) { struct drm_crtc *crtc; struct drm_crtc_state *crtc_state; struct drm_crtc_commit *commit; int i; - for_each_crtc_in_state(state, crtc, crtc_state, i) { - commit = state->crtcs[i].commit; + for_each_crtc_in_state(old_state, crtc, crtc_state, i) { + commit = old_state->crtcs[i].commit; if (!commit) continue; @@ -1584,16 +1592,16 @@ EXPORT_SYMBOL(drm_atomic_helper_commit_hw_done); /** * drm_atomic_helper_commit_cleanup_done - signal completion of commit - * @state: new modeset state to be committed + * @old_state: atomic state object with old state structures * - * This signals completion of the atomic update @state, including any cleanup - * work. If used, it must be called right before calling + * This signals completion of the atomic update @old_state, including any + * cleanup work. If used, it must be called right before calling * drm_atomic_state_put(). * * This is part of the atomic helper support for nonblocking commits, see * drm_atomic_helper_setup_commit() for an overview. */ -void drm_atomic_helper_commit_cleanup_done(struct drm_atomic_state *state) +void drm_atomic_helper_commit_cleanup_done(struct drm_atomic_state *old_state) { struct drm_crtc *crtc; struct drm_crtc_state *crtc_state; @@ -1601,8 +1609,8 @@ void drm_atomic_helper_commit_cleanup_done(struct drm_atomic_state *state) int i; long ret; - for_each_crtc_in_state(state, crtc, crtc_state, i) { - commit = state->crtcs[i].commit; + for_each_crtc_in_state(old_state, crtc, crtc_state, i) { + commit = old_state->crtcs[i].commit; if (WARN_ON(!commit)) continue; diff --git a/include/drm/drm_modeset_helper_vtables.h b/include/drm/drm_modeset_helper_vtables.h index 72478cf82147..69c3974bf133 100644 --- a/include/drm/drm_modeset_helper_vtables.h +++ b/include/drm/drm_modeset_helper_vtables.h @@ -999,10 +999,14 @@ struct drm_mode_config_helper_funcs { * to implement blocking and nonblocking commits easily. It is not used * by the atomic helpers * - * This hook should first commit the given atomic state to the hardware. - * But drivers can add more waiting calls at the start of their - * implementation, e.g. to wait for driver-internal request for implicit - * syncing, before starting to commit the update to the hardware. + * This function is called when the new atomic state has already been + * swapped into the various state pointers. The passed in state + * therefore contains copies of the old/previous state. This hook should + * commit the new state into hardware. Note that the helpers have + * already waited for preceeding atomic commits and fences, but drivers + * can add more waiting calls at the start of their implementation, e.g. + * to wait for driver-internal request for implicit syncing, before + * starting to commit the update to the hardware. * * After the atomic update is committed to the hardware this hook needs * to call drm_atomic_helper_commit_hw_done(). Then wait for the upate -- 2.20.1