Split out from my big nonblocking atomic commit helper code as prep work. While add it, also add some neat asciiart to document how it's supposed to be used.
v2: Resurrect misplaced hunk in the kerneldoc.
Tested-by: Tomeu Vizoso tomeu.vizoso@collabora.com Cc: Maarten Lankhorst maarten.lankhorst@linux.intel.com Cc: Tomeu Vizoso tomeu.vizoso@gmail.com Cc: Daniel Stone daniels@collabora.com Tested-by: Liviu Dudau Liviu.Dudau@arm.com Signed-off-by: Daniel Vetter daniel.vetter@intel.com --- drivers/gpu/drm/drm_atomic.c | 22 +++++++ drivers/gpu/drm/drm_crtc.c | 3 + drivers/gpu/drm/drm_fops.c | 6 ++ include/drm/drmP.h | 1 + include/drm/drm_atomic.h | 6 ++ include/drm/drm_crtc.h | 149 +++++++++++++++++++++++++++++++++++++++++-- 6 files changed, 181 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c index 5e4b820a977c..d99ab2f6663f 100644 --- a/drivers/gpu/drm/drm_atomic.c +++ b/drivers/gpu/drm/drm_atomic.c @@ -33,6 +33,20 @@
#include "drm_crtc_internal.h"
+static void crtc_commit_free(struct kref *kref) +{ + struct drm_crtc_commit *commit = + container_of(kref, struct drm_crtc_commit, ref); + + kfree(commit); +} + +void drm_crtc_commit_put(struct drm_crtc_commit *commit) +{ + kref_put(&commit->ref, crtc_commit_free); +} +EXPORT_SYMBOL(drm_crtc_commit_put); + /** * drm_atomic_state_default_release - * release memory initialized by drm_atomic_state_init @@ -148,6 +162,14 @@ void drm_atomic_state_default_clear(struct drm_atomic_state *state)
crtc->funcs->atomic_destroy_state(crtc, state->crtcs[i].state); + + if (state->crtcs[i].commit) { + kfree(state->crtcs[i].commit->event); + state->crtcs[i].commit->event = NULL; + drm_crtc_commit_put(state->crtcs[i].commit); + } + + state->crtcs[i].commit = NULL; state->crtcs[i].ptr = NULL; state->crtcs[i].state = NULL; } diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c index d3d0b4162e76..ce0569c3f942 100644 --- a/drivers/gpu/drm/drm_crtc.c +++ b/drivers/gpu/drm/drm_crtc.c @@ -669,6 +669,9 @@ int drm_crtc_init_with_planes(struct drm_device *dev, struct drm_crtc *crtc, crtc->dev = dev; crtc->funcs = funcs;
+ INIT_LIST_HEAD(&crtc->commit_list); + spin_lock_init(&crtc->commit_lock); + drm_modeset_lock_init(&crtc->mutex); ret = drm_mode_object_get(dev, &crtc->base, DRM_MODE_OBJECT_CRTC); if (ret) diff --git a/drivers/gpu/drm/drm_fops.c b/drivers/gpu/drm/drm_fops.c index 44b3ecdeca63..323c238fcac7 100644 --- a/drivers/gpu/drm/drm_fops.c +++ b/drivers/gpu/drm/drm_fops.c @@ -686,6 +686,12 @@ void drm_send_event_locked(struct drm_device *dev, struct drm_pending_event *e) { assert_spin_locked(&dev->event_lock);
+ if (e->completion) { + /* ->completion might disappear as soon as it signalled. */ + complete_all(e->completion); + e->completion = NULL; + } + if (e->fence) { fence_signal(e->fence); fence_put(e->fence); diff --git a/include/drm/drmP.h b/include/drm/drmP.h index 15fe4a21a9da..dce655abd23d 100644 --- a/include/drm/drmP.h +++ b/include/drm/drmP.h @@ -283,6 +283,7 @@ struct drm_ioctl_desc {
/* Event queued up for userspace to read */ struct drm_pending_event { + struct completion *completion; struct drm_event *event; struct fence *fence; struct list_head link; diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h index a16861c882aa..856a9c85a838 100644 --- a/include/drm/drm_atomic.h +++ b/include/drm/drm_atomic.h @@ -30,6 +30,12 @@
#include <drm/drm_crtc.h>
+void drm_crtc_commit_put(struct drm_crtc_commit *commit); +static inline void drm_crtc_commit_get(struct drm_crtc_commit *commit) +{ + kref_get(&commit->ref); +} + struct drm_atomic_state * __must_check drm_atomic_state_alloc(struct drm_device *dev); void drm_atomic_state_clear(struct drm_atomic_state *state); diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h index 520abafc9d00..14aa8212e30f 100644 --- a/include/drm/drm_crtc.h +++ b/include/drm/drm_crtc.h @@ -727,9 +727,6 @@ struct drm_crtc_funcs { * @gamma_store: gamma ramp values * @helper_private: mid-layer private data * @properties: property tracking for this CRTC - * @state: current atomic state for this CRTC - * @acquire_ctx: per-CRTC implicit acquire context used by atomic drivers for - * legacy IOCTLs * * Each CRTC may have one or more connectors associated with it. This structure * allows the CRTC to be controlled. @@ -786,11 +783,37 @@ struct drm_crtc {
struct drm_object_properties properties;
+ /** + * @state: + * + * Current atomic state for this CRTC. + */ struct drm_crtc_state *state;
- /* - * For legacy crtc IOCTLs so that atomic drivers can get at the locking - * acquire context. + /** + * @commit_list: + * + * List of &drm_crtc_commit structures tracking pending commits. + * Protected by @commit_lock. This list doesn't hold its own full + * reference, but burrows it from the ongoing commit. Commit entries + * must be removed from this list once the commit is fully completed, + * but before it's correspoding &drm_atomic_state gets destroyed. + */ + struct list_head commit_list; + + /** + * @commit_lock: + * + * Spinlock to protect @commit_list. + */ + spinlock_t commit_lock; + + /** + * @acquire_ctx: + * + * Per-CRTC implicit acquire context used by atomic drivers for legacy + * IOCTLs, so that atomic drivers can get at the locking acquire + * context. */ struct drm_modeset_acquire_ctx *acquire_ctx; }; @@ -1732,6 +1755,111 @@ struct drm_bridge { void *driver_private; };
+/** + * struct drm_crtc_commit - track modeset commits on a CRTC + * + * This structure is used to track pending modeset changes and atomic commit on + * a per-CRTC basis. Since updating the list should never block this structure + * is reference counted to allow waiters to safely wait on an event to complete, + * without holding any locks. + * + * It has 3 different events in total to allow a fine-grained synchronoization + * between outstanding updates:: + * + * atomic commit thread hardware + * + * write new state into hardware ----> ... + * signal hw_done + * switch to new state on next + * ... v/hblank + * + * wait for buffers to show up ... + * + * ... send completion irq + * irq handler signals flip_done + * cleanup old buffers + * + * signal cleanup_done + * + * wait for flip_done <---- + * clean up atomic state + * + * The important bit to know is that cleanup_done is the terminal event, but the + * ordering between flip_done and hw_done is entirely up to the specific driver + * and modeset state change. + * + * For an implementation of how to use this look at + * drm_atomic_helper_setup_commit() from the atomic helper library. + */ +struct drm_crtc_commit { + /** + * @crtc: + * + * DRM CRTC for this commit. + */ + struct drm_crtc *crtc; + + /** + * @ref: + * + * Reference count for this structure. Needed to allow blocking on + * completions without the risk of the completion disappearing + * meanwhile. + */ + struct kref ref; + + /** + * @flip_done: + * + * Will be signaled when the hardware has flipped to the new set of + * buffers. Signals at the same time as when the drm event for this + * commit is sent to userspace, or when an out-fence is singalled. Note + * that for most hardware, in most cases this happens after @hw_done is + * signalled. + */ + struct completion flip_done; + + /** + * @hw_done: + * + * Will be signalled when all hw register changes for this commit have + * been written out. Especially when disabling a pipe this can be much + * later than than @flip_done, since that can signal already when the + * screen goes black, whereas to fully shut down a pipe more register + * I/O is required. + * + * Note that this does not need to include separately reference-counted + * resources like backing storage buffer pinning, or runtime pm + * management. + */ + struct completion hw_done; + + /** + * @cleanup_done: + * + * Will be signalled after old buffers have been cleaned up again by + * calling drm_atomic_helper_cleanup_planes(). Since this can only + * happen after a vblank wait completed it might be a bit later. This + * completion is useful to throttle updates and avoid hardware updates + * getting ahead of the buffer cleanup too much. + */ + struct completion cleanup_done; + + /** + * @commit_entry: + * + * Entry on the per-CRTC commit_list. Protected by crtc->commit_lock. + */ + struct list_head commit_entry; + + /** + * @event: + * + * &drm_pending_vblank_event pointer to clean up private events. + */ + struct drm_pending_vblank_event *event; +}; + struct __drm_planes_state { struct drm_plane *ptr; struct drm_plane_state *state; @@ -1740,6 +1868,7 @@ struct __drm_planes_state { struct __drm_crtcs_state { struct drm_crtc *ptr; struct drm_crtc_state *state; + struct drm_crtc_commit *commit; };
struct __drm_connnectors_state { @@ -1770,6 +1899,14 @@ struct drm_atomic_state { struct __drm_connnectors_state *connectors;
struct drm_modeset_acquire_ctx *acquire_ctx; + + /** + * @commit_work: + * + * Work item which can be used by the driver or helpers to execute the + * commit without blocking. + */ + struct work_struct commit_work; };