Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1709237

[PATCH 5/7] staging: typec: tcpm: Add timeout when waiting for role swap completion

Show all headers | View raw

The Type-C protocol manager state machine could fail, which might result
in role swap requests from user space to hang forever. Add a generous
timeout when waiting for role swaps to complete to avoid this situation.

Originally-from: Badhri Jagan Sridharan <badhri@google.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
 drivers/staging/typec/tcpm.c | 21 +++++++++++++++------
 drivers/staging/typec/tcpm.h |  3 ++-
 2 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/drivers/staging/typec/tcpm.c b/drivers/staging/typec/tcpm.c
index cf498c68c4af..515bec1807d7 100644
--- a/drivers/staging/typec/tcpm.c
+++ b/drivers/staging/typec/tcpm.c
@@ -3166,9 +3166,12 @@ static int tcpm_dr_set(const struct typec_capability *cap,
 	tcpm_set_state(port, DR_SWAP_SEND, 0);
 	mutex_unlock(&port->lock);
 
-	wait_for_completion(&port->swap_complete);
+	if (!wait_for_completion_timeout(&port->swap_complete,
+				msecs_to_jiffies(PD_ROLE_SWAP_TIMEOUT)))
+		ret = -ETIMEDOUT;
+	else
+		ret = port->swap_status;
 
-	ret = port->swap_status;
 	goto swap_unlock;
 
 port_unlock:
@@ -3223,9 +3226,12 @@ static int tcpm_pr_set(const struct typec_capability *cap,
 	tcpm_set_state(port, PR_SWAP_SEND, 0);
 	mutex_unlock(&port->lock);
 
-	wait_for_completion(&port->swap_complete);
+	if (!wait_for_completion_timeout(&port->swap_complete,
+				msecs_to_jiffies(PD_ROLE_SWAP_TIMEOUT)))
+		ret = -ETIMEDOUT;
+	else
+		ret = port->swap_status;
 
-	ret = port->swap_status;
 	goto swap_unlock;
 
 port_unlock:
@@ -3260,9 +3266,12 @@ static int tcpm_vconn_set(const struct typec_capability *cap,
 	tcpm_set_state(port, VCONN_SWAP_SEND, 0);
 	mutex_unlock(&port->lock);
 
-	wait_for_completion(&port->swap_complete);
+	if (!wait_for_completion_timeout(&port->swap_complete,
+				msecs_to_jiffies(PD_ROLE_SWAP_TIMEOUT)))
+		ret = -ETIMEDOUT;
+	else
+		ret = port->swap_status;
 
-	ret = port->swap_status;
 	goto swap_unlock;
 
 port_unlock:
diff --git a/drivers/staging/typec/tcpm.h b/drivers/staging/typec/tcpm.h
index 4c6b38cb2c8a..374cea44a84a 100644
--- a/drivers/staging/typec/tcpm.h
+++ b/drivers/staging/typec/tcpm.h
@@ -34,7 +34,8 @@ enum typec_cc_polarity {
 };
 
 /* Time to wait for TCPC to complete transmit */
-#define PD_T_TCPC_TX_TIMEOUT  100
+#define PD_T_TCPC_TX_TIMEOUT	100		/* in ms	*/
+#define PD_ROLE_SWAP_TIMEOUT	(MSEC_PER_SEC * 10)
 
 enum tcpm_transmit_status {
 	TCPC_TX_SUCCESS = 0,
-- 
2.7.4

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH 1/7] staging: typec: tcpm: Constify alternate modes Guenter Roeck <linux@roeck-us.net> - 2017-08-11 06:20 +0200
  [PATCH 5/7] staging: typec: tcpm: Add timeout when waiting for role swap completion Guenter Roeck <linux@roeck-us.net> - 2017-08-11 06:20 +0200
  [PATCH 7/7] staging: typec: tcpm: Check cc status before entering SRC_TRY_DEBOUCE Guenter Roeck <linux@roeck-us.net> - 2017-08-11 06:20 +0200
  [PATCH 3/7] staging: typec: tcpm: Set default state after error recovery based on port type Guenter Roeck <linux@roeck-us.net> - 2017-08-11 06:20 +0200
  [PATCH 4/7] staging: typec: tcpm: Select default state based on port type Guenter Roeck <linux@roeck-us.net> - 2017-08-11 06:20 +0200

csiph-web