Commit 2d99ced7 authored by Rob Clark's avatar Rob Clark
Browse files

drm/msm: async commit support 



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: default avatarRob Clark <robdclark@chromium.org>
Reviewed-by: default avatarSean Paul <sean@poorly.run>
parent e35a29d5

drivers/gpu/drm/msm/msm_atomic.c

+155 −1
Original line number Diff line number Diff line
@@ -26,6 +26,95 @@ 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.
@@ -47,9 +136,25 @@ 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, prepare the

	 * current update:

	 */

	kms->funcs->prepare_commit(kms, state);



	/*
@@ -59,6 +164,49 @@ 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:

	 */
@@ -67,12 +215,18 @@ 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);

}

drivers/gpu/drm/msm/msm_drv.c

+1 −0
Original line number Diff line number Diff line
@@ -473,6 +473,7 @@ 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);

drivers/gpu/drm/msm/msm_drv.h

+4 −0
Original line number Diff line number Diff line
@@ -221,8 +221,12 @@ 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);

drivers/gpu/drm/msm/msm_kms.h

+50 −0
Original line number Diff line number Diff line
@@ -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 ->prepare_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);

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