From: Rob Clark robdclark@chromium.org
Now that flush/wait/complete is decoupled from the "synchronous" part of atomic commit_tail(), add support to defer flush to a timer that expires shortly before vblank for async commits. In this way, multiple atomic commits (for example, cursor updates) can be coalesced into a single flush at the end of the frame.
v2: don't hold lock over ->wait_flush(), to avoid locking interaction that was causing fps drop when combining page flips or non-async atomic commits and lots of legacy cursor updates
Signed-off-by: Rob Clark robdclark@chromium.org --- drivers/gpu/drm/msm/msm_atomic.c | 156 ++++++++++++++++++++++++++++++- drivers/gpu/drm/msm/msm_drv.c | 1 + drivers/gpu/drm/msm/msm_drv.h | 4 + drivers/gpu/drm/msm/msm_kms.h | 50 ++++++++++ 4 files changed, 210 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/msm/msm_atomic.c b/drivers/gpu/drm/msm/msm_atomic.c index 614fb9c5bb58..8f8f74337cb4 100644 --- a/drivers/gpu/drm/msm/msm_atomic.c +++ b/drivers/gpu/drm/msm/msm_atomic.c @@ -29,6 +29,95 @@ int msm_atomic_prepare_fb(struct drm_plane *plane, return msm_framebuffer_prepare(new_state->fb, kms->aspace); }
+static void msm_atomic_async_commit(struct msm_kms *kms, int crtc_idx) +{ + unsigned crtc_mask = BIT(crtc_idx); + + mutex_lock(&kms->commit_lock); + + if (!(kms->pending_crtc_mask & crtc_mask)) { + mutex_unlock(&kms->commit_lock); + return; + } + + kms->pending_crtc_mask &= ~crtc_mask; + + kms->funcs->enable_commit(kms); + + /* + * Flush hardware updates: + */ + DRM_DEBUG_ATOMIC("triggering async commit\n"); + kms->funcs->flush_commit(kms, crtc_mask); + mutex_unlock(&kms->commit_lock); + + /* + * Wait for flush to complete: + */ + kms->funcs->wait_flush(kms, crtc_mask); + + mutex_lock(&kms->commit_lock); + kms->funcs->complete_commit(kms, crtc_mask); + mutex_unlock(&kms->commit_lock); + kms->funcs->disable_commit(kms); +} + +static enum hrtimer_restart msm_atomic_pending_timer(struct hrtimer *t) +{ + struct msm_pending_timer *timer = container_of(t, + struct msm_pending_timer, timer); + struct msm_drm_private *priv = timer->kms->dev->dev_private; + + queue_work(priv->wq, &timer->work); + + return HRTIMER_NORESTART; +} + +static void msm_atomic_pending_work(struct work_struct *work) +{ + struct msm_pending_timer *timer = container_of(work, + struct msm_pending_timer, work); + + msm_atomic_async_commit(timer->kms, timer->crtc_idx); +} + +void msm_atomic_init_pending_timer(struct msm_pending_timer *timer, + struct msm_kms *kms, int crtc_idx) +{ + timer->kms = kms; + timer->crtc_idx = crtc_idx; + hrtimer_init(&timer->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS); + timer->timer.function = msm_atomic_pending_timer; + INIT_WORK(&timer->work, msm_atomic_pending_work); +} + +static bool can_do_async(struct drm_atomic_state *state, + struct drm_crtc **async_crtc) +{ + struct drm_connector_state *connector_state; + struct drm_connector *connector; + struct drm_crtc_state *crtc_state; + struct drm_crtc *crtc; + int i, num_crtcs = 0; + + if (!(state->legacy_cursor_update || state->async_update)) + return false; + + /* any connector change, means slow path: */ + for_each_new_connector_in_state(state, connector, connector_state, i) + return false; + + for_each_new_crtc_in_state(state, crtc, crtc_state, i) { + if (drm_atomic_crtc_needs_modeset(crtc_state)) + return false; + if (++num_crtcs > 1) + return false; + *async_crtc = crtc; + } + + return true; +} + /* Get bitmask of crtcs that will need to be flushed. The bitmask * can be used with for_each_crtc_mask() iterator, to iterate * effected crtcs without needing to preserve the atomic state. @@ -50,9 +139,25 @@ void msm_atomic_commit_tail(struct drm_atomic_state *state) struct drm_device *dev = state->dev; struct msm_drm_private *priv = dev->dev_private; struct msm_kms *kms = priv->kms; + struct drm_crtc *async_crtc = NULL; unsigned crtc_mask = get_crtc_mask(state); + bool async = kms->funcs->vsync_time && + can_do_async(state, &async_crtc);
kms->funcs->enable_commit(kms); + + /* + * Ensure any previous (potentially async) commit has + * completed: + */ + kms->funcs->wait_flush(kms, crtc_mask); + + mutex_lock(&kms->commit_lock); + + /* + * Now that there is no in-progress flush is complete, + * prepare the current update: + */ kms->funcs->prepare_commit(kms, state);
/* @@ -62,6 +167,49 @@ void msm_atomic_commit_tail(struct drm_atomic_state *state) drm_atomic_helper_commit_planes(dev, state, 0); drm_atomic_helper_commit_modeset_enables(dev, state);
+ if (async) { + struct msm_pending_timer *timer = + &kms->pending_timers[drm_crtc_index(async_crtc)]; + + /* async updates are limited to single-crtc updates: */ + WARN_ON(crtc_mask != drm_crtc_mask(async_crtc)); + + /* + * Start timer if we don't already have an update pending + * on this crtc: + */ + if (!(kms->pending_crtc_mask & crtc_mask)) { + ktime_t vsync_time, wakeup_time; + + kms->pending_crtc_mask |= crtc_mask; + + vsync_time = kms->funcs->vsync_time(kms, async_crtc); + wakeup_time = ktime_sub(vsync_time, ms_to_ktime(1)); + + hrtimer_start(&timer->timer, wakeup_time, + HRTIMER_MODE_ABS); + } + + kms->funcs->disable_commit(kms); + mutex_unlock(&kms->commit_lock); + + /* + * At this point, from drm core's perspective, we + * are done with the atomic update, so we can just + * go ahead and signal that it is done: + */ + drm_atomic_helper_commit_hw_done(state); + drm_atomic_helper_cleanup_planes(dev, state); + + return; + } + + /* + * If there is any async flush pending on updated crtcs, fold + * them into the current flush. + */ + kms->pending_crtc_mask &= ~crtc_mask; + /* * Flush hardware updates: */ @@ -70,12 +218,18 @@ void msm_atomic_commit_tail(struct drm_atomic_state *state) kms->funcs->commit(kms, state); } kms->funcs->flush_commit(kms, crtc_mask); + mutex_unlock(&kms->commit_lock);
+ /* + * Wait for flush to complete: + */ kms->funcs->wait_flush(kms, crtc_mask); + + mutex_lock(&kms->commit_lock); kms->funcs->complete_commit(kms, crtc_mask); + mutex_unlock(&kms->commit_lock); kms->funcs->disable_commit(kms);
drm_atomic_helper_commit_hw_done(state); - drm_atomic_helper_cleanup_planes(dev, state); } diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c index 336a6d0a4cd3..65262a993440 100644 --- a/drivers/gpu/drm/msm/msm_drv.c +++ b/drivers/gpu/drm/msm/msm_drv.c @@ -532,6 +532,7 @@ static int msm_drm_init(struct device *dev, struct drm_driver *drv) ddev->mode_config.normalize_zpos = true;
if (kms) { + kms->dev = ddev; ret = kms->funcs->hw_init(kms); if (ret) { DRM_DEV_ERROR(dev, "kms hw init failed: %d\n", ret); diff --git a/drivers/gpu/drm/msm/msm_drv.h b/drivers/gpu/drm/msm/msm_drv.h index 79d480a7d97d..7d164d5c18b4 100644 --- a/drivers/gpu/drm/msm/msm_drv.h +++ b/drivers/gpu/drm/msm/msm_drv.h @@ -222,8 +222,12 @@ struct msm_format { uint32_t pixel_format; };
+struct msm_pending_timer; + int msm_atomic_prepare_fb(struct drm_plane *plane, struct drm_plane_state *new_state); +void msm_atomic_init_pending_timer(struct msm_pending_timer *timer, + struct msm_kms *kms, int crtc_idx); void msm_atomic_commit_tail(struct drm_atomic_state *state); struct drm_atomic_state *msm_atomic_state_alloc(struct drm_device *dev); void msm_atomic_state_clear(struct drm_atomic_state *state); diff --git a/drivers/gpu/drm/msm/msm_kms.h b/drivers/gpu/drm/msm/msm_kms.h index 811f5e2c2405..5eafc9686d29 100644 --- a/drivers/gpu/drm/msm/msm_kms.h +++ b/drivers/gpu/drm/msm/msm_kms.h @@ -33,6 +33,20 @@ struct msm_kms_funcs {
/* * Atomic commit handling: + * + * Note that in the case of async commits, the funcs which take + * a crtc_mask (ie. ->flush_commit(), and ->complete_commit()) + * might not be evenly balanced with ->prepare_commit(), however + * each crtc that effected by a ->perpare_commit() (potentially + * multiple times) will eventually (at end of vsync period) be + * flushed and completed. + * + * This has some implications about tracking of cleanup state, + * for example SMP blocks to release after commit completes. Ie. + * cleanup state should be also duplicated in the various + * duplicate_state() methods, as the current cleanup state at + * ->complete_commit() time may have accumulated cleanup work + * from multiple commits. */
/** @@ -45,6 +59,14 @@ struct msm_kms_funcs { void (*enable_commit)(struct msm_kms *kms); void (*disable_commit)(struct msm_kms *kms);
+ /** + * If the kms backend supports async commit, it should implement + * this method to return the time of the next vsync. This is + * used to determine a time slightly before vsync, for the async + * commit timer to run and complete an async commit. + */ + ktime_t (*vsync_time)(struct msm_kms *kms, struct drm_crtc *crtc); + /** * Prepare for atomic commit. This is called after any previous * (async or otherwise) commit has completed. @@ -109,20 +131,48 @@ struct msm_kms_funcs { #endif };
+struct msm_kms; + +/* + * A per-crtc timer for pending async atomic flushes. Scheduled to expire + * shortly before vblank to flush pending async updates. + */ +struct msm_pending_timer { + struct hrtimer timer; + struct work_struct work; + struct msm_kms *kms; + unsigned crtc_idx; +}; + struct msm_kms { const struct msm_kms_funcs *funcs; + struct drm_device *dev;
/* irq number to be passed on to drm_irq_install */ int irq;
/* mapper-id used to request GEM buffer mapped for scanout: */ struct msm_gem_address_space *aspace; + + /* + * For async commit, where ->flush_commit() and later happens + * from the crtc's pending_timer close to end of the frame: + */ + struct mutex commit_lock; + unsigned pending_crtc_mask; + struct msm_pending_timer pending_timers[MAX_CRTCS]; };
static inline void msm_kms_init(struct msm_kms *kms, const struct msm_kms_funcs *funcs) { + unsigned i; + + mutex_init(&kms->commit_lock); kms->funcs = funcs; + + for (i = 0; i < ARRAY_SIZE(kms->pending_timers); i++) + msm_atomic_init_pending_timer(&kms->pending_timers[i], kms, i); }
struct msm_kms *mdp4_kms_init(struct drm_device *dev);