Skip to contentSkip to conversation

Bluetooth: Defer SCO setup if mode change is pending

PATCH In review Marcel Holtmann 2 participants 9 messages Jul 19, 2010 – Jul 27, 2010

Subsystems (2)
Bluetooth drivers Bluetooth
lore
Share & tools
lore

Marcel Holtmann

author maintainer
#0 lore raw

PATCH 1/1 Bluetooth: Defer SCO setup if mode change is pending

Signed-off-by Marcel Holtmann <[email protected]>
---
 include/net/bluetooth/hci_core.h |    2 +
 net/bluetooth/hci_conn.c         |   32 ++++++++++++++++++++++++---
 net/bluetooth/hci_event.c        |   43 ++++++++++++++++---------------------
 3 files changed, 49 insertions(+), 28 deletions(-)
include/net/bluetooth/hci_core.h +2 -0
index 350b3e6..8b28962 100644
@@ -256,6 +256,7 @@ enum {
 	HCI_CONN_ENCRYPT_PEND,
 	HCI_CONN_RSWITCH_PEND,
 	HCI_CONN_MODE_CHANGE_PEND,
+	HCI_CONN_SCO_SETUP_PEND,
 };
 
 static inline void hci_conn_hash_init(struct hci_dev *hdev)

@@ -336,6 +337,7 @@ void hci_acl_connect(struct hci_conn *conn);
 void hci_acl_disconn(struct hci_conn *conn, __u8 reason);
 void hci_add_sco(struct hci_conn *conn, __u16 handle);
 void hci_setup_sync(struct hci_conn *conn, __u16 handle);
+void hci_sco_setup(struct hci_conn *conn, __u8 status);
 
 struct hci_conn *hci_conn_add(struct hci_dev *hdev, int type, bdaddr_t *dst);
 int hci_conn_del(struct hci_conn *conn);
net/bluetooth/hci_conn.c +28 -4
index e9fef83..0b1e460 100644
@@ -155,6 +155,27 @@ void hci_setup_sync(struct hci_conn *conn, __u16 handle)
 	hci_send_cmd(hdev, HCI_OP_SETUP_SYNC_CONN, sizeof(cp), &cp);
 }
 
+/* Device _must_ be locked */
+void hci_sco_setup(struct hci_conn *conn, __u8 status)
+{
+	struct hci_conn *sco = conn->link;
+
+	BT_DBG("%p", conn);
+
+	if (!sco)
+		return;
+
+	if (!status) {
+		if (lmp_esco_capable(conn->hdev))
+			hci_setup_sync(sco, conn->handle);
+		else
+			hci_add_sco(sco, conn->handle);
+	} else {
+		hci_proto_connect_cfm(sco, status);
+		hci_conn_del(sco);
+	}
+}
+
 static void hci_conn_timeout(unsigned long arg)
 {
 	struct hci_conn *conn = (void *) arg;

@@ -385,10 +406,13 @@ struct hci_conn *hci_connect(struct hci_dev *hdev, int type, bdaddr_t *dst, __u8
 		acl->power_save = 1;
 		hci_conn_enter_active_mode(acl);
 
-		if (lmp_esco_capable(hdev))
-			hci_setup_sync(sco, acl->handle);
-		else
-			hci_add_sco(sco, acl->handle);
+		if (test_bit(HCI_CONN_MODE_CHANGE_PEND, &acl->pend)) {
+			/* defer SCO setup until mode change completed */
+			set_bit(HCI_CONN_SCO_SETUP_PEND, &acl->pend);
+			return sco;
+		}
+
+		hci_sco_setup(acl, 0x00);
 	}
 
 	return sco;
net/bluetooth/hci_event.c +19 -24

79 lines not on this page · raw message

Signature · 1 line
1.7.1.1
#1 lore raw

Marcel:

Quoted 6 lines · Marcel Holtmann
net/bluetooth/hci_conn.c +0 -2
@@ -385,10 +406,13 @@ struct hci_conn *hci_connect(struct hci_dev *hdev, int type, bdaddr_t *dst, __u8
 		acl->power_save = 1;
 		hci_conn_enter_active_mode(acl);
 
-		if (lmp_esco_capable(hdev))
-			hci_setup_sync(sco, acl->handle);

net/bluetooth/hci_conn.c struct hci_conn *hci_connect(struct hci_dev *hdev, int type, bdaddr_t *dst, __u8 · line 416

Quoted 10 lines
net/bluetooth/hci_conn.c +7 -2
-		else
-			hci_add_sco(sco, acl->handle);
+		if (test_bit(HCI_CONN_MODE_CHANGE_PEND, &acl->pend)) {
+			/* defer SCO setup until mode change completed */
+			set_bit(HCI_CONN_SCO_SETUP_PEND, &acl->pend);
+			return sco;
+		}
+
+		hci_sco_setup(acl, 0x00);
 	}

Not in love with the "fake" status passed here, but the overall change to centralize this functionality provides a nice cleanup from the original patch and makes the code more readable and maintainable.

Quoted 18 lines
net/bluetooth/hci_conn.c +0 -0
 	return sco;
net/bluetooth/hci_event.c +0 -3
index 2069c3b..461413c 100644
@@ -775,9 +775,6 @@ static void hci_cs_sniff_mode(struct hci_dev *hdev, __u8 status)
 
 	BT_DBG("%s status 0x%x", hdev->name, status);
 
-	if (!status)
-		return;
-
 	cp = hci_sent_cmd_data(hdev, HCI_OP_SNIFF_MODE);
 	if (!cp)
 		return;

@@ -785,8 +782,13 @@ static void hci_cs_sniff_mode(struct hci_dev *hdev, __u8 status)
 	hci_dev_lock(hdev);

net/bluetooth/hci_event.c static void hci_cs_sniff_mode(struct hci_dev *hdev, __u8 status) · line 790

Quoted 10 lines
net/bluetooth/hci_event.c +6 -2
 
 	conn = hci_conn_hash_lookup_handle(hdev, __le16_to_cpu(cp->handle));
-	if (conn)
-		clear_bit(HCI_CONN_MODE_CHANGE_PEND, &conn->pend);
+	if (conn) {
+		if (status)
+			clear_bit(HCI_CONN_MODE_CHANGE_PEND, &conn->pend);
+
+		if (test_and_clear_bit(HCI_CONN_SCO_SETUP_PEND, &conn->pend))
+			hci_sco_setup(conn, status);

Probably the subject for another patch, but has there been any reported issue where idle_timeout is set short enough that the timer expires after exit sniff mode has been requested but before the mode change event has been received?

Got back from other duties late tonight, so I didn't get testing fully finished. In particular, I need to see what happens when idle_timeout is set very low ex < 10. I'll let you know the results first thing in the morning. If everything is good, I'll regenerate the patch with original hcidump log included

Signature · 3 lines
Ron Shaffer
Employee of the Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
author maintainer
#2 lore raw

Hi Ron,

Quoted 4 lines
Quoted 4 lines
net/bluetooth/hci_conn.c +0 -0
@@ -385,10 +406,13 @@ struct hci_conn *hci_connect(struct hci_dev *hdev, int type, bdaddr_t *dst, __u8
 		acl->power_save = 1;
 		hci_conn_enter_active_mode(acl);
Quoted 16 lines

net/bluetooth/hci_conn.c struct hci_conn *hci_connect(struct hci_dev *hdev, int type, bdaddr_t *dst, __u8 · line 416

Quoted 12 lines
net/bluetooth/hci_conn.c +7 -4
-		if (lmp_esco_capable(hdev))
-			hci_setup_sync(sco, acl->handle);
-		else
-			hci_add_sco(sco, acl->handle);
+		if (test_bit(HCI_CONN_MODE_CHANGE_PEND, &acl->pend)) {
+			/* defer SCO setup until mode change completed */
+			set_bit(HCI_CONN_SCO_SETUP_PEND, &acl->pend);
+			return sco;
+		}
+
+		hci_sco_setup(acl, 0x00);
 	}

Not in love with the "fake" status passed here, but the overall change to centralize this functionality provides a nice cleanup from the original patch and makes the code more readable and maintainable.

yeah, the 0x00 looks funny here. We could add a comment explaining it, but it does make sense in the end.

Quoted 18 lines
Quoted 18 lines
net/bluetooth/hci_conn.c +0 -0
 	return sco;
net/bluetooth/hci_event.c +0 -3
index 2069c3b..461413c 100644
@@ -775,9 +775,6 @@ static void hci_cs_sniff_mode(struct hci_dev *hdev, __u8 status)
 
 	BT_DBG("%s status 0x%x", hdev->name, status);
 
-	if (!status)
-		return;
-
 	cp = hci_sent_cmd_data(hdev, HCI_OP_SNIFF_MODE);
 	if (!cp)
 		return;

@@ -785,8 +782,13 @@ static void hci_cs_sniff_mode(struct hci_dev *hdev, __u8 status)
 	hci_dev_lock(hdev);
Quoted 14 lines

net/bluetooth/hci_event.c static void hci_cs_sniff_mode(struct hci_dev *hdev, __u8 status) · line 790

Quoted 9 lines
net/bluetooth/hci_event.c +6 -2
 	conn = hci_conn_hash_lookup_handle(hdev, __le16_to_cpu(cp->handle));
-	if (conn)
-		clear_bit(HCI_CONN_MODE_CHANGE_PEND, &conn->pend);
+	if (conn) {
+		if (status)
+			clear_bit(HCI_CONN_MODE_CHANGE_PEND, &conn->pend);
+
+		if (test_and_clear_bit(HCI_CONN_SCO_SETUP_PEND, &conn->pend))
+			hci_sco_setup(conn, status);

Probably the subject for another patch, but has there been any reported issue where idle_timeout is set short enough that the timer expires after exit sniff mode has been requested but before the mode change event has been received?

I see that this could potentially happen. The timer is not suppose to be running during that transaction. It should be only started when the mode change has been completed. That needs fixing, but not in this patch.

Regards

Marcel

#3 lore raw

PATCH v2 1/1 Bluetooth: Defer SCO setup if mode change is pending

From: Marcel Holtmann <[email protected]>

Certain headsets such as the Motorola H350 will reject SCO and eSCO connection requests while the ACL is transitioning from sniff mode to active mode. Add synchronization so that SCO and eSCO connection requests will wait until the ACL has fully transitioned to active mode.

< HCI Command: Exit Sniff Mode (0x02|0x0004) plen 2
handle 12

Quoted 1 line

HCI Event: Command Status (0x0f) plen 4

    Exit Sniff Mode (0x02|0x0004) status 0x00 ncmd 1
< HCI Command:  Setup Synchronous Connection (0x01|0x0028) plen 17
    handle 12 voice setting 0x0040
Quoted 1 line

HCI Event: Command Status (0x0f) plen 4

    Setup Synchronous Connection (0x01|0x0028) status 0x00 ncmd 1
Quoted 1 line

HCI Event: Number of Completed Packets (0x13) plen 5

handle 12 packets 1

Quoted 1 line

HCI Event: Mode Change (0x14) plen 6

    status 0x00 handle 12 mode 0x00 interval 0
    Mode: Active
Quoted 1 line

HCI Event: Synchronous Connect Complete (0x2c) plen 17

status 0x10 handle 14 bdaddr 00:1A:0E:50:28:A4 type SCO
Error: Connection Accept Timeout Exceeded

Signed-off-by Marcel Holtmann <[email protected]>
Signed-off-by Ron Shaffer <[email protected]>
---
 include/net/bluetooth/hci_core.h |    2 +
 net/bluetooth/hci_conn.c         |   32 ++++++++++++++++++++++---
 net/bluetooth/hci_event.c        |   47 ++++++++++++++++++-------------------
 3 files changed, 53 insertions(+), 28 deletions(-)
include/net/bluetooth/hci_core.h +2 -0
index e42f6ed..edf3dfe 100644
@@ -250,6 +250,7 @@ enum {
 	HCI_CONN_ENCRYPT_PEND,
 	HCI_CONN_RSWITCH_PEND,
 	HCI_CONN_MODE_CHANGE_PEND,
+	HCI_CONN_SCO_SETUP_PEND,
 };
 
 static inline void hci_conn_hash_init(struct hci_dev *hdev)

@@ -330,6 +331,7 @@ void hci_acl_connect(struct hci_conn *conn);
 void hci_acl_disconn(struct hci_conn *conn, __u8 reason);
 void hci_add_sco(struct hci_conn *conn, __u16 handle);
 void hci_setup_sync(struct hci_conn *conn, __u16 handle);
+void hci_sco_setup(struct hci_conn *conn, __u8 status);
 
 struct hci_conn *hci_conn_add(struct hci_dev *hdev, int type, bdaddr_t *dst);
 int hci_conn_del(struct hci_conn *conn);
net/bluetooth/hci_conn.c +28 -4
index b10e3cd..805a22c 100644
@@ -155,6 +155,27 @@ void hci_setup_sync(struct hci_conn *conn, __u16 handle)
 	hci_send_cmd(hdev, HCI_OP_SETUP_SYNC_CONN, sizeof(cp), &cp);
 }
 
+/* Device _must_ be locked */
+void hci_sco_setup(struct hci_conn *conn, __u8 status)
+{
+	struct hci_conn *sco = conn->link;
+
+	BT_DBG("%p", conn);
+
+	if (!sco)
+		return;
+
+	if (!status) {
+		if (lmp_esco_capable(conn->hdev))
+			hci_setup_sync(sco, conn->handle);
+		else
+			hci_add_sco(sco, conn->handle);
+	} else {
+		hci_proto_connect_cfm(sco, status);
+		hci_conn_del(sco);
+	}
+}
+
 static void hci_conn_timeout(unsigned long arg)
 {
 	struct hci_conn *conn = (void *) arg;

@@ -380,10 +401,13 @@ struct hci_conn *hci_connect(struct hci_dev *hdev, int type, bdaddr_t *dst, __u8
 		acl->power_save = 1;
 		hci_conn_enter_active_mode(acl);
 
-		if (lmp_esco_capable(hdev))
-			hci_setup_sync(sco, acl->handle);
-		else
-			hci_add_sco(sco, acl->handle);
+		if (test_bit(HCI_CONN_MODE_CHANGE_PEND, &acl->pend)) {
+			/* defer SCO setup until mode change completed */
+			set_bit(HCI_CONN_SCO_SETUP_PEND, &acl->pend);
+			return sco;
+		}
+
+		hci_sco_setup(acl, 0x00);
 	}
 
 	return sco;
net/bluetooth/hci_event.c +23 -24

83 lines not on this page · raw message

Signature · 5 lines
1.7.0.2
--
Ron Shaffer
Employee of the Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
author maintainer
#4 lore raw

Hi Ron,

Quoted 22 lines
net/bluetooth/hci_event.c +2 -5
index 6c57fc7..9aee8c5 100644
@@ -775,9 +775,6 @@ static void hci_cs_sniff_mode(struct hci_dev *hdev, __u8 status)
 
 	BT_DBG("%s status 0x%x", hdev->name, status);
 
-	if (!status)
-		return;
-
 	cp = hci_sent_cmd_data(hdev, HCI_OP_SNIFF_MODE);
 	if (!cp)
 		return;

@@ -785,8 +782,15 @@ static void hci_cs_sniff_mode(struct hci_dev *hdev, __u8 status)
 	hci_dev_lock(hdev);
 
 	conn = hci_conn_hash_lookup_handle(hdev, __le16_to_cpu(cp->handle));
-	if (conn)
-		clear_bit(HCI_CONN_MODE_CHANGE_PEND, &conn->pend);
+	if (conn) {
+		if (status) {

net/bluetooth/hci_event.c static void hci_cs_sniff_mode(struct hci_dev *hdev, __u8 status) · line 796

Quoted 10 lines
net/bluetooth/hci_event.c +7 -0
+			clear_bit(HCI_CONN_MODE_CHANGE_PEND, &conn->pend);
+
+			if (test_and_clear_bit(HCI_CONN_SCO_SETUP_PEND,
+					&conn->pend))
+				hci_sco_setup(conn, status);
+		}
+	}
 
 	hci_dev_unlock(hdev);
 }

this change now makes it worse, please revert to initial

	if (!status)
		return;

check at the top and the just do

	if (conn) {
		clear_bit(HCI_CONN_MODE_CHANGE_PEND, &conn->pend);

		if (test_and_clear_bit(HCI_CONN_SCO_SETUP_PEND, &conn->pend))
			hci_sco_setup(conn, status);
	}

The only reason why I moved the status check down, because I was not thinking straight and overlooked that in case of success we don't wanna do a single thing here.

Quoted 18 lines
net/bluetooth/hci_event.c +2 -5
@@ -798,9 +802,6 @@ static void hci_cs_exit_sniff_mode(struct hci_dev *hdev, __u8 status)
 
 	BT_DBG("%s status 0x%x", hdev->name, status);
 
-	if (!status)
-		return;
-
 	cp = hci_sent_cmd_data(hdev, HCI_OP_EXIT_SNIFF_MODE);
 	if (!cp)
 		return;

@@ -808,8 +809,15 @@ static void hci_cs_exit_sniff_mode(struct hci_dev *hdev, __u8 status)
 	hci_dev_lock(hdev);
 
 	conn = hci_conn_hash_lookup_handle(hdev, __le16_to_cpu(cp->handle));
-	if (conn)
-		clear_bit(HCI_CONN_MODE_CHANGE_PEND, &conn->pend);
+	if (conn) {
+		if (status) {

net/bluetooth/hci_event.c static void hci_cs_exit_sniff_mode(struct hci_dev *hdev, __u8 status) · line 823

Quoted 10 lines
net/bluetooth/hci_event.c +7 -0
+			clear_bit(HCI_CONN_MODE_CHANGE_PEND, &conn->pend);
+
+			if (test_and_clear_bit(HCI_CONN_SCO_SETUP_PEND,
+					&conn->pend))
+				hci_sco_setup(conn, status);
+		}
+	}
 
 	hci_dev_unlock(hdev);
 }

Same applies here btw.

Quoted 24 lines
net/bluetooth/hci_event.c +2 -14
@@ -915,20 +923,8 @@ static inline void hci_conn_complete_evt(struct hci_dev *hdev, struct sk_buff *s
 	} else
 		conn->state = BT_CLOSED;
 
-	if (conn->type == ACL_LINK) {
-		struct hci_conn *sco = conn->link;
-		if (sco) {
-			if (!ev->status) {
-				if (lmp_esco_capable(hdev))
-					hci_setup_sync(sco, conn->handle);
-				else
-					hci_add_sco(sco, conn->handle);
-			} else {
-				hci_proto_connect_cfm(sco, ev->status);
-				hci_conn_del(sco);
-			}
-		}
-	}
+	if (conn->type == ACL_LINK)
+		hci_sco_setup(conn, ev->status);
 
 	if (ev->status) {
 		hci_proto_connect_cfm(conn, ev->status);

net/bluetooth/hci_event.c static inline void hci_mode_change_evt(struct hci_dev *hdev, struct sk_buff *skb · line 1481

Quoted 8 lines
net/bluetooth/hci_event.c +3 -0
@@ -1478,6 +1474,9 @@ static inline void hci_mode_change_evt(struct hci_dev *hdev, struct sk_buff *skb
 				conn->power_save = 1;
 			else
 				conn->power_save = 0;
+		} else if (test_and_clear_bit(HCI_CONN_SCO_SETUP_PEND,
+				&conn->pend)) {
+			hci_sco_setup(conn, ev->status);
 		}
 	}

Please don't do else if here. Just add a separate check like I had in my initial patch. We don't wanna depend on two flags pending flags set here. If the SCO setup is pending, then we execute it. No matter how we reached that point. It is important that even if we receive a mode change without us triggering it, that we clear any potential SCO pending flag.

Regards

Marcel

#5 lore raw

Marcel:

Quoted 49 lines

Hi Ron,

Quoted 22 lines
net/bluetooth/hci_event.c +2 -5
index 6c57fc7..9aee8c5 100644
@@ -775,9 +775,6 @@ static void hci_cs_sniff_mode(struct hci_dev *hdev, __u8 status)
 
 	BT_DBG("%s status 0x%x", hdev->name, status);
 
-	if (!status)
-		return;
-
 	cp = hci_sent_cmd_data(hdev, HCI_OP_SNIFF_MODE);
 	if (!cp)
 		return;

@@ -785,8 +782,15 @@ static void hci_cs_sniff_mode(struct hci_dev *hdev, __u8 status)
 	hci_dev_lock(hdev);
 
 	conn = hci_conn_hash_lookup_handle(hdev, __le16_to_cpu(cp->handle));
-	if (conn)
-		clear_bit(HCI_CONN_MODE_CHANGE_PEND, &conn->pend);
+	if (conn) {
+		if (status) {

net/bluetooth/hci_event.c static void hci_cs_sniff_mode(struct hci_dev *hdev, __u8 status) · line 796

Quoted 10 lines
net/bluetooth/hci_event.c +7 -0
+			clear_bit(HCI_CONN_MODE_CHANGE_PEND, &conn->pend);
+
+			if (test_and_clear_bit(HCI_CONN_SCO_SETUP_PEND,
+					&conn->pend))
+				hci_sco_setup(conn, status);
+		}
+	}
 
 	hci_dev_unlock(hdev);
 }

this change now makes it worse, please revert to initial

	if (!status)
		return;

check at the top and the just do

	if (conn) {
		clear_bit(HCI_CONN_MODE_CHANGE_PEND, &conn->pend);

		if (test_and_clear_bit(HCI_CONN_SCO_SETUP_PEND, &conn->pend))
			hci_sco_setup(conn, status);
	}
Quoted 3 lines

The only reason why I moved the status check down, because I was not thinking straight and overlooked that in case of success we don't wanna do a single thing here.

Makes sense. Done.

Quoted 27 lines
Quoted 27 lines
net/bluetooth/hci_event.c +9 -5
@@ -798,9 +802,6 @@ static void hci_cs_exit_sniff_mode(struct hci_dev *hdev, __u8 status)
 
 	BT_DBG("%s status 0x%x", hdev->name, status);
 
-	if (!status)
-		return;
-
 	cp = hci_sent_cmd_data(hdev, HCI_OP_EXIT_SNIFF_MODE);
 	if (!cp)
 		return;

@@ -808,8 +809,15 @@ static void hci_cs_exit_sniff_mode(struct hci_dev *hdev, __u8 status)
 	hci_dev_lock(hdev);
 
 	conn = hci_conn_hash_lookup_handle(hdev, __le16_to_cpu(cp->handle));
-	if (conn)
-		clear_bit(HCI_CONN_MODE_CHANGE_PEND, &conn->pend);
+	if (conn) {
+		if (status) {
+			clear_bit(HCI_CONN_MODE_CHANGE_PEND, &conn->pend);
+
+			if (test_and_clear_bit(HCI_CONN_SCO_SETUP_PEND,
+					&conn->pend))
+				hci_sco_setup(conn, status);
+		}
+	}
Quoted 4 lines

net/bluetooth/hci_event.c static void hci_cs_exit_sniff_mode(struct hci_dev *hdev, __u8 status) · line 823

Quoted 2 lines
net/bluetooth/hci_event.c +0 -0
 	hci_dev_unlock(hdev);
 }

Same applies here btw.

Same. Done.

Quoted 32 lines
Quoted 32 lines
net/bluetooth/hci_event.c +5 -14
@@ -915,20 +923,8 @@ static inline void hci_conn_complete_evt(struct hci_dev *hdev, struct sk_buff *s
 	} else
 		conn->state = BT_CLOSED;
 
-	if (conn->type == ACL_LINK) {
-		struct hci_conn *sco = conn->link;
-		if (sco) {
-			if (!ev->status) {
-				if (lmp_esco_capable(hdev))
-					hci_setup_sync(sco, conn->handle);
-				else
-					hci_add_sco(sco, conn->handle);
-			} else {
-				hci_proto_connect_cfm(sco, ev->status);
-				hci_conn_del(sco);
-			}
-		}
-	}
+	if (conn->type == ACL_LINK)
+		hci_sco_setup(conn, ev->status);
 
 	if (ev->status) {
 		hci_proto_connect_cfm(conn, ev->status);

@@ -1478,6 +1474,9 @@ static inline void hci_mode_change_evt(struct hci_dev *hdev, struct sk_buff *skb
 				conn->power_save = 1;
 			else
 				conn->power_save = 0;
+		} else if (test_and_clear_bit(HCI_CONN_SCO_SETUP_PEND,
+				&conn->pend)) {
+			hci_sco_setup(conn, ev->status);
 		}
Quoted 8 lines

net/bluetooth/hci_event.c static inline void hci_mode_change_evt(struct hci_dev *hdev, struct sk_buff *skb · line 1481

Quoted 1 line
net/bluetooth/hci_event.c +0 -0
 	}

Please don't do else if here. Just add a separate check like I had in my initial patch. We don't wanna depend on two flags pending flags set here. If the SCO setup is pending, then we execute it. No matter how we reached that point. It is important that even if we receive a mode change without us triggering it, that we clear any potential SCO pending flag.

Hmmm. I know I found a bug here, but I can't remember how it manifested itself. Today, I can't reproduce it, so either I was seeing things or I'm losing it.

I'll revert it back, and if I run across the issue again, we can fix it later.

Signature · 3 lines
Ron Shaffer
Employee of the Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
author maintainer
#6 lore raw

Hi Ron,

Quoted 128 lines
Quoted 47 lines
Quoted 22 lines
net/bluetooth/hci_event.c +2 -5
index 6c57fc7..9aee8c5 100644
@@ -775,9 +775,6 @@ static void hci_cs_sniff_mode(struct hci_dev *hdev, __u8 status)
 
 	BT_DBG("%s status 0x%x", hdev->name, status);
 
-	if (!status)
-		return;
-
 	cp = hci_sent_cmd_data(hdev, HCI_OP_SNIFF_MODE);
 	if (!cp)
 		return;

@@ -785,8 +782,15 @@ static void hci_cs_sniff_mode(struct hci_dev *hdev, __u8 status)
 	hci_dev_lock(hdev);
 
 	conn = hci_conn_hash_lookup_handle(hdev, __le16_to_cpu(cp->handle));
-	if (conn)
-		clear_bit(HCI_CONN_MODE_CHANGE_PEND, &conn->pend);
+	if (conn) {
+		if (status) {

net/bluetooth/hci_event.c static void hci_cs_sniff_mode(struct hci_dev *hdev, __u8 status) · line 796

Quoted 10 lines
net/bluetooth/hci_event.c +7 -0
+			clear_bit(HCI_CONN_MODE_CHANGE_PEND, &conn->pend);
+
+			if (test_and_clear_bit(HCI_CONN_SCO_SETUP_PEND,
+					&conn->pend))
+				hci_sco_setup(conn, status);
+		}
+	}
 
 	hci_dev_unlock(hdev);
 }

this change now makes it worse, please revert to initial

	if (!status)
		return;

check at the top and the just do

	if (conn) {
		clear_bit(HCI_CONN_MODE_CHANGE_PEND, &conn->pend);

		if (test_and_clear_bit(HCI_CONN_SCO_SETUP_PEND, &conn->pend))
			hci_sco_setup(conn, status);
	}
Quoted 3 lines

The only reason why I moved the status check down, because I was not thinking straight and overlooked that in case of success we don't wanna do a single thing here.

Makes sense. Done.

Quoted 27 lines
Quoted 27 lines
net/bluetooth/hci_event.c +9 -5
@@ -798,9 +802,6 @@ static void hci_cs_exit_sniff_mode(struct hci_dev *hdev, __u8 status)
 
 	BT_DBG("%s status 0x%x", hdev->name, status);
 
-	if (!status)
-		return;
-
 	cp = hci_sent_cmd_data(hdev, HCI_OP_EXIT_SNIFF_MODE);
 	if (!cp)
 		return;

@@ -808,8 +809,15 @@ static void hci_cs_exit_sniff_mode(struct hci_dev *hdev, __u8 status)
 	hci_dev_lock(hdev);
 
 	conn = hci_conn_hash_lookup_handle(hdev, __le16_to_cpu(cp->handle));
-	if (conn)
-		clear_bit(HCI_CONN_MODE_CHANGE_PEND, &conn->pend);
+	if (conn) {
+		if (status) {
+			clear_bit(HCI_CONN_MODE_CHANGE_PEND, &conn->pend);
+
+			if (test_and_clear_bit(HCI_CONN_SCO_SETUP_PEND,
+					&conn->pend))
+				hci_sco_setup(conn, status);
+		}
+	}
Quoted 4 lines

net/bluetooth/hci_event.c static void hci_cs_exit_sniff_mode(struct hci_dev *hdev, __u8 status) · line 823

Quoted 2 lines
net/bluetooth/hci_event.c +0 -0
 	hci_dev_unlock(hdev);
 }

Same applies here btw.

Same. Done.

Quoted 32 lines
Quoted 32 lines
net/bluetooth/hci_event.c +5 -14
@@ -915,20 +923,8 @@ static inline void hci_conn_complete_evt(struct hci_dev *hdev, struct sk_buff *s
 	} else
 		conn->state = BT_CLOSED;
 
-	if (conn->type == ACL_LINK) {
-		struct hci_conn *sco = conn->link;
-		if (sco) {
-			if (!ev->status) {
-				if (lmp_esco_capable(hdev))
-					hci_setup_sync(sco, conn->handle);
-				else
-					hci_add_sco(sco, conn->handle);
-			} else {
-				hci_proto_connect_cfm(sco, ev->status);
-				hci_conn_del(sco);
-			}
-		}
-	}
+	if (conn->type == ACL_LINK)
+		hci_sco_setup(conn, ev->status);
 
 	if (ev->status) {
 		hci_proto_connect_cfm(conn, ev->status);

@@ -1478,6 +1474,9 @@ static inline void hci_mode_change_evt(struct hci_dev *hdev, struct sk_buff *skb
 				conn->power_save = 1;
 			else
 				conn->power_save = 0;
+		} else if (test_and_clear_bit(HCI_CONN_SCO_SETUP_PEND,
+				&conn->pend)) {
+			hci_sco_setup(conn, ev->status);
 		}
Quoted 8 lines

net/bluetooth/hci_event.c static inline void hci_mode_change_evt(struct hci_dev *hdev, struct sk_buff *skb · line 1481

Quoted 1 line
net/bluetooth/hci_event.c +0 -0
 	}

Please don't do else if here. Just add a separate check like I had in my initial patch. We don't wanna depend on two flags pending flags set here. If the SCO setup is pending, then we execute it. No matter how we reached that point. It is important that even if we receive a mode change without us triggering it, that we clear any potential SCO pending flag.

Quoted 6 lines

Hmmm. I know I found a bug here, but I can't remember how it manifested itself. Today, I can't reproduce it, so either I was seeing things or I'm losing it.

I'll revert it back, and if I run across the issue again, we can fix it later.

please send v3 of this patch then.

Regards

Marcel

#7 lore raw

PATCH v3 1/1 Bluetooth: Defer SCO setup if mode change is pending

From: Marcel Holtmann <[email protected]>

Certain headsets such as the Motorola H350 will reject SCO and eSCO connection requests while the ACL is transitioning from sniff mode to active mode. Add synchronization so that SCO and eSCO connection requests will wait until the ACL has fully transitioned to active mode.

< HCI Command: Exit Sniff Mode (0x02|0x0004) plen 2
handle 12

Quoted 1 line

HCI Event: Command Status (0x0f) plen 4

    Exit Sniff Mode (0x02|0x0004) status 0x00 ncmd 1
< HCI Command:  Setup Synchronous Connection (0x01|0x0028) plen 17
    handle 12 voice setting 0x0040
Quoted 1 line

HCI Event: Command Status (0x0f) plen 4

    Setup Synchronous Connection (0x01|0x0028) status 0x00 ncmd 1
Quoted 1 line

HCI Event: Number of Completed Packets (0x13) plen 5

handle 12 packets 1

Quoted 1 line

HCI Event: Mode Change (0x14) plen 6

    status 0x00 handle 12 mode 0x00 interval 0
    Mode: Active
Quoted 1 line

HCI Event: Synchronous Connect Complete (0x2c) plen 17

status 0x10 handle 14 bdaddr 00:1A:0E:50:28:A4 type SCO
Error: Connection Accept Timeout Exceeded

Signed-off-by Marcel Holtmann <[email protected]>
Signed-off-by Ron Shaffer <[email protected]>
---
 include/net/bluetooth/hci_core.h |    2 ++
 net/bluetooth/hci_conn.c         |   32 ++++++++++++++++++++++++++++----
 net/bluetooth/hci_event.c        |   33 +++++++++++++++++----------------
 3 files changed, 47 insertions(+), 20 deletions(-)
include/net/bluetooth/hci_core.h +2 -0
index e42f6ed..edf3dfe 100644
@@ -250,6 +250,7 @@ enum {
 	HCI_CONN_ENCRYPT_PEND,
 	HCI_CONN_RSWITCH_PEND,
 	HCI_CONN_MODE_CHANGE_PEND,
+	HCI_CONN_SCO_SETUP_PEND,
 };
 
 static inline void hci_conn_hash_init(struct hci_dev *hdev)

@@ -330,6 +331,7 @@ void hci_acl_connect(struct hci_conn *conn);
 void hci_acl_disconn(struct hci_conn *conn, __u8 reason);
 void hci_add_sco(struct hci_conn *conn, __u16 handle);
 void hci_setup_sync(struct hci_conn *conn, __u16 handle);
+void hci_sco_setup(struct hci_conn *conn, __u8 status);
 
 struct hci_conn *hci_conn_add(struct hci_dev *hdev, int type, bdaddr_t *dst);
 int hci_conn_del(struct hci_conn *conn);
net/bluetooth/hci_conn.c +28 -4
index b10e3cd..805a22c 100644
@@ -155,6 +155,27 @@ void hci_setup_sync(struct hci_conn *conn, __u16 handle)
 	hci_send_cmd(hdev, HCI_OP_SETUP_SYNC_CONN, sizeof(cp), &cp);
 }
 
+/* Device _must_ be locked */
+void hci_sco_setup(struct hci_conn *conn, __u8 status)
+{
+	struct hci_conn *sco = conn->link;
+
+	BT_DBG("%p", conn);
+
+	if (!sco)
+		return;
+
+	if (!status) {
+		if (lmp_esco_capable(conn->hdev))
+			hci_setup_sync(sco, conn->handle);
+		else
+			hci_add_sco(sco, conn->handle);
+	} else {
+		hci_proto_connect_cfm(sco, status);
+		hci_conn_del(sco);
+	}
+}
+
 static void hci_conn_timeout(unsigned long arg)
 {
 	struct hci_conn *conn = (void *) arg;

@@ -380,10 +401,13 @@ struct hci_conn *hci_connect(struct hci_dev *hdev, int type, bdaddr_t *dst, __u8
 		acl->power_save = 1;
 		hci_conn_enter_active_mode(acl);
 
-		if (lmp_esco_capable(hdev))
-			hci_setup_sync(sco, acl->handle);
-		else
-			hci_add_sco(sco, acl->handle);
+		if (test_bit(HCI_CONN_MODE_CHANGE_PEND, &acl->pend)) {
+			/* defer SCO setup until mode change completed */
+			set_bit(HCI_CONN_SCO_SETUP_PEND, &acl->pend);
+			return sco;
+		}
+
+		hci_sco_setup(acl, 0x00);
 	}
 
 	return sco;
net/bluetooth/hci_event.c +17 -16
index 6c57fc7..4fda049 100644
@@ -785,9 +785,14 @@ static void hci_cs_sniff_mode(struct hci_dev *hdev, __u8 status)
 	hci_dev_lock(hdev);
 
 	conn = hci_conn_hash_lookup_handle(hdev, __le16_to_cpu(cp->handle));
-	if (conn)
+	if (conn) {
 		clear_bit(HCI_CONN_MODE_CHANGE_PEND, &conn->pend);
 
+		if (test_and_clear_bit(HCI_CONN_SCO_SETUP_PEND,
+				&conn->pend))
+			hci_sco_setup(conn, status);
+	}
+
 	hci_dev_unlock(hdev);
 }
 

@@ -808,9 +813,14 @@ static void hci_cs_exit_sniff_mode(struct hci_dev *hdev, __u8 status)
 	hci_dev_lock(hdev);
 
 	conn = hci_conn_hash_lookup_handle(hdev, __le16_to_cpu(cp->handle));
-	if (conn)
+	if (conn) {
 		clear_bit(HCI_CONN_MODE_CHANGE_PEND, &conn->pend);
 
+		if (test_and_clear_bit(HCI_CONN_SCO_SETUP_PEND,
+				&conn->pend))
+			hci_sco_setup(conn, status);
+	}
+
 	hci_dev_unlock(hdev);
 }
 

@@ -915,20 +925,8 @@ static inline void hci_conn_complete_evt(struct hci_dev *hdev, struct sk_buff *s
 	} else
 		conn->state = BT_CLOSED;
 
-	if (conn->type == ACL_LINK) {
-		struct hci_conn *sco = conn->link;
-		if (sco) {
-			if (!ev->status) {
-				if (lmp_esco_capable(hdev))
-					hci_setup_sync(sco, conn->handle);
-				else
-					hci_add_sco(sco, conn->handle);
-			} else {
-				hci_proto_connect_cfm(sco, ev->status);
-				hci_conn_del(sco);
-			}
-		}
-	}
+	if (conn->type == ACL_LINK)
+		hci_sco_setup(conn, ev->status);
 
 	if (ev->status) {
 		hci_proto_connect_cfm(conn, ev->status);

@@ -1479,6 +1477,9 @@ static inline void hci_mode_change_evt(struct hci_dev *hdev, struct sk_buff *skb
 			else
 				conn->power_save = 0;
 		}
+
+		if (test_and_clear_bit(HCI_CONN_SCO_SETUP_PEND, &conn->pend))
+			hci_sco_setup(conn, ev->status);
 	}
 
 	hci_dev_unlock(hdev);
Signature · 5 lines
1.7.0.2
--
Ron Shaffer
Employee of the Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
author maintainer
#8 lore raw

Hi Ron,

Quoted 22 lines

Certain headsets such as the Motorola H350 will reject SCO and eSCO connection requests while the ACL is transitioning from sniff mode to active mode. Add synchronization so that SCO and eSCO connection requests will wait until the ACL has fully transitioned to active mode.

< HCI Command: Exit Sniff Mode (0x02|0x0004) plen 2
handle 12

Quoted 1 line

HCI Event: Command Status (0x0f) plen 4

    Exit Sniff Mode (0x02|0x0004) status 0x00 ncmd 1
< HCI Command:  Setup Synchronous Connection (0x01|0x0028) plen 17
    handle 12 voice setting 0x0040
Quoted 1 line

HCI Event: Command Status (0x0f) plen 4

    Setup Synchronous Connection (0x01|0x0028) status 0x00 ncmd 1
Quoted 1 line

HCI Event: Number of Completed Packets (0x13) plen 5

handle 12 packets 1

Quoted 1 line

HCI Event: Mode Change (0x14) plen 6

    status 0x00 handle 12 mode 0x00 interval 0
    Mode: Active
Quoted 1 line

HCI Event: Synchronous Connect Complete (0x2c) plen 17

status 0x10 handle 14 bdaddr 00:1A:0E:50:28:A4 type SCO
Error: Connection Accept Timeout Exceeded

Quoted 7 lines
Signed-off-by Marcel Holtmann <[email protected]>
Signed-off-by Ron Shaffer <[email protected]>
---
 include/net/bluetooth/hci_core.h |    2 ++
 net/bluetooth/hci_conn.c         |   32 ++++++++++++++++++++++++++++----
 net/bluetooth/hci_event.c        |   33 +++++++++++++++++----------------
 3 files changed, 47 insertions(+), 20 deletions(-)

I did a small cleanup, but patch has been applied now.

Regards

Marcel