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Commit 8bfd3d1f authored by Ingrid Gallardo's avatar Ingrid Gallardo Committed by Gerrit - the friendly Code Review server
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drm/msm/sde: wait for vsync before rsc amc mode 



When driver switch the rsc state from clock
mode to amc mode, a race condition can happen
where driver doesn't wait for the vsync before
the switch to amc mode happens.
This change, adds a refcount to make sure rsc
waits for the vsync before the mode switch.

Change-Id: I8db60afebc8bf91d56a1b71e6643d0db70230a5c
Signed-off-by: default avatarIngrid Gallardo <ingridg@codeaurora.org>
parent 223afe42

drivers/gpu/drm/msm/sde/sde_encoder.c

+12 −0
Original line number Diff line number Diff line
@@ -1511,6 +1511,7 @@ static int _sde_encoder_update_rsc_client( 
	struct drm_crtc *primary_crtc;

	int pipe = -1;

	int rc = 0;

	int wait_refcount;



	if (!drm_enc || !drm_enc->dev) {

		SDE_ERROR("invalid encoder arguments\n");
@@ -1598,6 +1599,12 @@ static int _sde_encoder_update_rsc_client( 
		return ret;

	}



	if (wait_vblank_crtc_id)

		wait_refcount =

			sde_rsc_client_get_vsync_refcount(sde_enc->rsc_client);

	SDE_EVT32_VERBOSE(DRMID(drm_enc), wait_vblank_crtc_id, wait_refcount,

			SDE_EVTLOG_FUNC_ENTRY);



	if (crtc->base.id != wait_vblank_crtc_id) {

		primary_crtc = drm_crtc_find(drm_enc->dev, wait_vblank_crtc_id);

		if (!primary_crtc) {
@@ -1635,6 +1642,11 @@ static int _sde_encoder_update_rsc_client( 
		SDE_EVT32(DRMID(drm_enc), wait_vblank_crtc_id, wait_count,

				SDE_EVTLOG_ERROR);



	if (wait_refcount)

		sde_rsc_client_reset_vsync_refcount(sde_enc->rsc_client);

	SDE_EVT32_VERBOSE(DRMID(drm_enc), wait_vblank_crtc_id, wait_refcount,

			SDE_EVTLOG_FUNC_EXIT);



	return ret;

}

drivers/gpu/drm/msm/sde_rsc.c

+94 −0
Original line number Diff line number Diff line
@@ -561,6 +561,23 @@ static int sde_rsc_switch_to_clk(struct sde_rsc_priv *rsc, 
			msleep(PRIMARY_VBLANK_WORST_CASE_MS);

		} else {

			*wait_vblank_crtc_id = rsc->primary_client->crtc_id;



			/* increase refcount, so we wait for the next vsync */

			atomic_inc(&rsc->rsc_vsync_wait);

			SDE_EVT32(atomic_read(&rsc->rsc_vsync_wait));

		}

	} else if (atomic_read(&rsc->rsc_vsync_wait)) {

		SDE_EVT32(rsc->primary_client, rsc->current_state,

			atomic_read(&rsc->rsc_vsync_wait));



		/* Wait for the vsync, if the refcount is set */

		rc = wait_event_timeout(rsc->rsc_vsync_waitq,

			atomic_read(&rsc->rsc_vsync_wait) == 0,

			msecs_to_jiffies(PRIMARY_VBLANK_WORST_CASE_MS*2));

		if (!rc) {

			pr_err("Timeout waiting for vsync\n");

			SDE_EVT32(atomic_read(&rsc->rsc_vsync_wait),

				SDE_EVTLOG_ERROR);

		}

	}

end:
@@ -600,6 +617,23 @@ static int sde_rsc_switch_to_vid(struct sde_rsc_priv *rsc, 
			msleep(PRIMARY_VBLANK_WORST_CASE_MS);

		} else {

			*wait_vblank_crtc_id = rsc->primary_client->crtc_id;



			/* increase refcount, so we wait for the next vsync */

			atomic_inc(&rsc->rsc_vsync_wait);

			SDE_EVT32(atomic_read(&rsc->rsc_vsync_wait));

		}

	} else if (atomic_read(&rsc->rsc_vsync_wait)) {

		SDE_EVT32(rsc->primary_client, rsc->current_state,

			atomic_read(&rsc->rsc_vsync_wait));



		/* Wait for the vsync, if the refcount is set */

		rc = wait_event_timeout(rsc->rsc_vsync_waitq,

			atomic_read(&rsc->rsc_vsync_wait) == 0,

			msecs_to_jiffies(PRIMARY_VBLANK_WORST_CASE_MS*2));

		if (!rc) {

			pr_err("Timeout waiting for vsync\n");

			SDE_EVT32(atomic_read(&rsc->rsc_vsync_wait),

				SDE_EVTLOG_ERROR);

		}

	}
@@ -607,6 +641,65 @@ static int sde_rsc_switch_to_vid(struct sde_rsc_priv *rsc, 
	return rc;

}



/**

 * sde_rsc_client_get_vsync_refcount() - returns the status of the vsync

 * refcount, to signal if the client needs to reset the refcounting logic

 * @client:	 Client pointer provided by sde_rsc_client_create().

 *

 * Return: value of the vsync refcount.

 */

int sde_rsc_client_get_vsync_refcount(

		struct sde_rsc_client *caller_client)

{

	struct sde_rsc_priv *rsc;



	if (!caller_client) {

		pr_err("invalid client for rsc state update\n");

		return -EINVAL;

	} else if (caller_client->rsc_index >= MAX_RSC_COUNT) {

		pr_err("invalid rsc index\n");

		return -EINVAL;

	}



	rsc = rsc_prv_list[caller_client->rsc_index];

	if (!rsc)

		return 0;



	return atomic_read(&rsc->rsc_vsync_wait);

}



/**

 * sde_rsc_client_reset_vsync_refcount() - reduces the refcounting

 * logic that waits for the vsync.

 * @client:	 Client pointer provided by sde_rsc_client_create().

 *

 * Return: zero if refcount was already zero.

 */

int sde_rsc_client_reset_vsync_refcount(

		struct sde_rsc_client *caller_client)

{

	struct sde_rsc_priv *rsc;

	int ret;



	if (!caller_client) {

		pr_err("invalid client for rsc state update\n");

		return -EINVAL;

	} else if (caller_client->rsc_index >= MAX_RSC_COUNT) {

		pr_err("invalid rsc index\n");

		return -EINVAL;

	}



	rsc = rsc_prv_list[caller_client->rsc_index];

	if (!rsc)

		return 0;



	ret = atomic_add_unless(&rsc->rsc_vsync_wait, -1, 0);

	wake_up_all(&rsc->rsc_vsync_waitq);

	SDE_EVT32(atomic_read(&rsc->rsc_vsync_wait));



	return ret;

}



/**

 * sde_rsc_client_is_state_update_complete() - check if state update is complete

 * RSC state transition is not complete until HW receives VBLANK signal. This
@@ -1307,6 +1400,7 @@ static int sde_rsc_probe(struct platform_device *pdev) 
	INIT_LIST_HEAD(&rsc->client_list);

	INIT_LIST_HEAD(&rsc->event_list);

	mutex_init(&rsc->client_lock);

	init_waitqueue_head(&rsc->rsc_vsync_waitq);



	pr_info("sde rsc index:%d probed successfully\n",

				SDE_RSC_INDEX + counter);

drivers/gpu/drm/msm/sde_rsc_priv.h

+4 −0
Original line number Diff line number Diff line
@@ -149,6 +149,8 @@ struct sde_rsc_timer_config { 
 *			and ab/ib vote on display rsc

 * master_drm:		Primary client waits for vsync on this drm object based

 *			on crtc id

 * rsc_vsync_wait:   Refcount to indicate if we have to wait for the vsync.

 * rsc_vsync_waitq:   Queue to wait for the vsync.

 */

struct sde_rsc_priv {

	u32 version;
@@ -177,6 +179,8 @@ struct sde_rsc_priv { 
	struct sde_rsc_client *primary_client;



	struct drm_device *master_drm;

	atomic_t rsc_vsync_wait;

	wait_queue_head_t rsc_vsync_waitq;

};



/**

include/linux/sde_rsc.h

+32 −0
Original line number Diff line number Diff line
@@ -185,6 +185,26 @@ int sde_rsc_client_state_update(struct sde_rsc_client *client, 
	struct sde_rsc_cmd_config *config, int crtc_id,

	int *wait_vblank_crtc_id);



/**

 * sde_rsc_client_get_vsync_refcount() - returns the status of the vsync

 * refcount, to signal if the client needs to reset the refcounting logic

 * @client:	 Client pointer provided by sde_rsc_client_create().

 *

 * Return: true if the state update has completed.

 */

int sde_rsc_client_get_vsync_refcount(

		struct sde_rsc_client *caller_client);



/**

 * sde_rsc_client_reset_vsync_refcount() - reduces the refcounting

 * logic that waits for the vsync.

 * @client:	 Client pointer provided by sde_rsc_client_create().

 *

 * Return: true if the state update has completed.

 */

int sde_rsc_client_reset_vsync_refcount(

		struct sde_rsc_client *caller_client);



/**

 * sde_rsc_client_is_state_update_complete() - check if state update is complete

 * RSC state transition is not complete until HW receives VBLANK signal. This
@@ -265,6 +285,18 @@ static inline int sde_rsc_client_state_update(struct sde_rsc_client *client, 
	return 0;

}



int sde_rsc_client_get_vsync_refcount(

		struct sde_rsc_client *caller_client)

{

	return 0;

}



int sde_rsc_client_reset_vsync_refcount(

		struct sde_rsc_client *caller_client)

{

	return 0;

}



static inline bool sde_rsc_client_is_state_update_complete(

		struct sde_rsc_client *caller_client)

{