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Commit 9ba5ace1 authored by Ajay Singh Parmar's avatar Ajay Singh Parmar Committed by Tatenda Chipeperekwa
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drm/msm/dp: protect power on/off functionalities with mutex 



In case of multiple threads trying to power on/off DP driver
simultaneously, un-clocked register access may happen. Use
session_lock in all conditions to avoid such scenario.

Change-Id: I6d8f82b3c37bf54965176dae50e0f9dca5343e2e
Signed-off-by: default avatarAjay Singh Parmar <aparmar@codeaurora.org>
Signed-off-by: default avatarTatenda Chipeperekwa <tatendac@codeaurora.org>
parent 320451eb

drivers/gpu/drm/msm/dp/dp_display.c

+21 −13
Original line number Diff line number Diff line
@@ -631,7 +631,7 @@ static void dp_display_host_deinit(struct dp_display_private *dp) 


static int dp_display_process_hpd_high(struct dp_display_private *dp)

{

	int rc = 0;

	int rc = -EINVAL;



	mutex_lock(&dp->session_lock);
@@ -643,7 +643,6 @@ static int dp_display_process_hpd_high(struct dp_display_private *dp) 
	}



	dp->is_connected = true;

	mutex_unlock(&dp->session_lock);



	dp->dp_display.max_pclk_khz = min(dp->parser->max_pclk_khz,

					dp->debug->max_pclk_khz);
@@ -665,9 +664,7 @@ static int dp_display_process_hpd_high(struct dp_display_private *dp) 
	 * ENOTCONN --> no downstream device connected

	 */

	if (rc == -ETIMEDOUT || rc == -ENOTCONN) {

		mutex_lock(&dp->session_lock);

		dp->is_connected = false;

		mutex_unlock(&dp->session_lock);

		goto end;

	}
@@ -676,22 +673,22 @@ static int dp_display_process_hpd_high(struct dp_display_private *dp) 


	dp_display_process_mst_hpd_high(dp, false);



	mutex_lock(&dp->session_lock);

	rc = dp->ctrl->on(dp->ctrl, dp->mst.mst_active,

				dp->panel->fec_en, false);

	if (rc) {

		dp->is_connected = false;

		mutex_unlock(&dp->session_lock);

		goto end;

	}

	mutex_unlock(&dp->session_lock);



	dp->process_hpd_connect = false;



	dp_display_process_mst_hpd_high(dp, true);

end:

	mutex_unlock(&dp->session_lock);



	if (!rc)

		dp_display_send_hpd_notification(dp);

end:



	return rc;

}
@@ -758,6 +755,7 @@ static int dp_display_usbpd_configure_cb(struct device *dev) 
			goto end;

	}



	mutex_lock(&dp->session_lock);

	dp_display_host_init(dp);



	/* check for hpd high */
@@ -765,7 +763,7 @@ static int dp_display_usbpd_configure_cb(struct device *dev) 
		queue_work(dp->wq, &dp->connect_work);

	else

		dp->process_hpd_connect = true;



	mutex_unlock(&dp->session_lock);

end:

	return rc;

}
@@ -884,8 +882,10 @@ static int dp_display_usbpd_disconnect_cb(struct device *dev) 
		goto end;

	}



	if (dp->debug->psm_enabled)

	mutex_lock(&dp->session_lock);

	if (dp->debug->psm_enabled && dp->core_initialized)

		dp->link->psm_config(dp->link, &dp->panel->link_info, true);

	mutex_unlock(&dp->session_lock);



	dp_display_disconnect_sync(dp);
@@ -934,11 +934,19 @@ static void dp_display_attention_work(struct work_struct *work) 
	struct dp_display_private *dp = container_of(work,

			struct dp_display_private, attention_work);



	if (dp->debug->mst_hpd_sim)

	mutex_lock(&dp->session_lock);



	if (dp->debug->mst_hpd_sim || !dp->core_initialized) {

		mutex_unlock(&dp->session_lock);

		goto mst_attention;

	}



	if (dp->link->process_request(dp->link))

	if (dp->link->process_request(dp->link)) {

		mutex_unlock(&dp->session_lock);

		goto cp_irq;

	}



	mutex_unlock(&dp->session_lock);



	if (dp->link->sink_request & DS_PORT_STATUS_CHANGED) {

		if (dp_display_is_sink_count_zero(dp)) {