Commit 39b138ea authored by Tomasz Figa's avatar Tomasz Figa Committed by Andrzej Hajda
Browse files

drm/rockchip: psr: Avoid redundant calls to .set() callback 



The first time after we call rockchip_drm_do_flush() after
rockchip_drm_psr_register(), we go from PSR_DISABLE to PSR_FLUSH. The
difference between PSR_DISABLE and PSR_FLUSH is whether or not we have a
delayed work pending - PSR is off in either state.  However
psr_set_state() only catches the transition from PSR_FLUSH to
PSR_DISABLE (which never happens), while going from PSR_DISABLE to
PSR_FLUSH triggers a call to psr->set() to disable PSR while it's
already disabled. This triggers the eDP PHY power-on sequence without
being shut down first and this seems to occasionally leave the encoder
unable to later enable PSR. Let's just simplify the state machine and
simply consider PSR_DISABLE and PSR_FLUSH the same state.

Signed-off-by: default avatarTomasz Figa <tfiga@chromium.org>
Signed-off-by: default avatarKristian H. Kristensen <hoegsberg@chromium.org>
Signed-off-by: default avatarThierry Escande <thierry.escande@collabora.com>
Signed-off-by: default avatarEnric Balletbo i Serra <enric.balletbo@collabora.com>
Tested-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: default avatarAndrzej Hajda <a.hajda@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180423105003.9004-25-enric.balletbo@collabora.com
parent a4169609

drivers/gpu/drm/rockchip/rockchip_drm_psr.c

+24 −56
Original line number Diff line number Diff line
@@ -20,19 +20,13 @@ 


#define PSR_FLUSH_TIMEOUT_MS	100



enum psr_state {

	PSR_FLUSH,

	PSR_ENABLE,

	PSR_DISABLE,

};



struct psr_drv {

	struct list_head	list;

	struct drm_encoder	*encoder;



	struct mutex		lock;

	bool			active;

	enum psr_state		state;

	bool			enabled;



	struct delayed_work	flush_work;
@@ -73,52 +67,22 @@ out: 
	return psr;

}



static void psr_set_state_locked(struct psr_drv *psr, enum psr_state state)

static int psr_set_state_locked(struct psr_drv *psr, bool enable)

{

	/*

	 * Allowed finite state machine:

	 *

	 *   PSR_ENABLE  < = = = = = >  PSR_FLUSH

	 *       | ^                        |

	 *       | |                        |

	 *       v |                        |

	 *   PSR_DISABLE < - - - - - - - - -

	 */

	if (state == psr->state || !psr->active)

		return;

	int ret;



	/* Already disabled in flush, change the state, but not the hardware */

	if (state == PSR_DISABLE && psr->state == PSR_FLUSH) {

		psr->state = state;

		return;

	}

	if (!psr->active)

		return -EINVAL;



	/* Actually commit the state change to hardware */

	switch (state) {

	case PSR_ENABLE:

		if (psr->set(psr->encoder, true))

			return;

		break;



	case PSR_DISABLE:

	case PSR_FLUSH:

		if (psr->set(psr->encoder, false))

			return;

		break;



	default:

		pr_err("%s: Unknown state %d\n", __func__, state);

		return;

	}

	if (enable == psr->enabled)

		return 0;



	psr->state = state;

}

	ret = psr->set(psr->encoder, enable);

	if (ret)

		return ret;



static void psr_set_state(struct psr_drv *psr, enum psr_state state)

{

	mutex_lock(&psr->lock);

	psr_set_state_locked(psr, state);

	mutex_unlock(&psr->lock);

	psr->enabled = enable;

	return 0;

}



static void psr_flush_handler(struct work_struct *work)
@@ -126,10 +90,8 @@ static void psr_flush_handler(struct work_struct *work) 
	struct psr_drv *psr = container_of(to_delayed_work(work),

					   struct psr_drv, flush_work);



	/* If the state has changed since we initiated the flush, do nothing */

	mutex_lock(&psr->lock);

	if (psr->state == PSR_FLUSH)

		psr_set_state_locked(psr, PSR_ENABLE);

	psr_set_state_locked(psr, true);

	mutex_unlock(&psr->lock);

}
@@ -171,6 +133,7 @@ int rockchip_drm_psr_deactivate(struct drm_encoder *encoder) 


	mutex_lock(&psr->lock);

	psr->active = false;

	psr->enabled = false;

	mutex_unlock(&psr->lock);

	cancel_delayed_work_sync(&psr->flush_work);
@@ -180,8 +143,13 @@ EXPORT_SYMBOL(rockchip_drm_psr_deactivate); 


static void rockchip_drm_do_flush(struct psr_drv *psr)

{

	psr_set_state(psr, PSR_FLUSH);

	mod_delayed_work(system_wq, &psr->flush_work, PSR_FLUSH_TIMEOUT_MS);

	cancel_delayed_work_sync(&psr->flush_work);



	mutex_lock(&psr->lock);

	if (!psr_set_state_locked(psr, false))

		mod_delayed_work(system_wq, &psr->flush_work,

				 PSR_FLUSH_TIMEOUT_MS);

	mutex_unlock(&psr->lock);

}



/**
@@ -250,8 +218,8 @@ int rockchip_drm_psr_register(struct drm_encoder *encoder, 
	INIT_DELAYED_WORK(&psr->flush_work, psr_flush_handler);

	mutex_init(&psr->lock);



	psr->active = true;

	psr->state = PSR_DISABLE;

	psr->active = false;

	psr->enabled = false;

	psr->encoder = encoder;

	psr->set = psr_set;

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