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From:   Sasha Levin <Alexander.Levin@microsoft.com>
To:     "stable@vger.kernel.org" <stable@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
CC:     Marcel Holtmann <marcel@holtmann.org>,
        Szymon Janc <szymon.janc@codecoup.pl>,
        Sasha Levin <Alexander.Levin@microsoft.com>
Subject: [PATCH AUTOSEL for 4.9 038/293] Bluetooth: Send HCI Set Event Mask
 Page 2 command only when needed
Thread-Topic: [PATCH AUTOSEL for 4.9 038/293] Bluetooth: Send HCI Set Event
 Mask Page 2 command only when needed
Thread-Index: AQHTz5j25TxXBdaOQkWMi0rvJBf+AQ==
Date:   Mon, 9 Apr 2018 00:23:19 +0000
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From: Marcel Holtmann <marcel@holtmann.org>

[ Upstream commit 313f6888c8fbb1bc8b36c9012ce4e1de848df696 ]

The Broadcom BCM20702 Bluetooth controller in ThinkPad-T530 devices
report support for the Set Event Mask Page 2 command, but actually do
return an error when trying to use it.

  < HCI Command: Read Local Supported Commands (0x04|0x0002) plen 0
  > HCI Event: Command Complete (0x0e) plen 68
       Read Local Supported Commands (0x04|0x0002) ncmd 1
         Status: Success (0x00)
         Commands: 162 entries
           ...
           Set Event Mask Page 2 (Octet 22 - Bit 2)
           ...

  < HCI Command: Set Event Mask Page 2 (0x03|0x0063) plen 8
         Mask: 0x0000000000000000
  > HCI Event: Command Complete (0x0e) plen 4
       Set Event Mask Page 2 (0x03|0x0063) ncmd 1
         Status: Unknown HCI Command (0x01)

Since these controllers do not support any feature that would require
the event mask page 2 to be modified, it is safe to not send this
command at all. The default value is all bits set to zero.

T:  Bus=3D01 Lev=3D02 Prnt=3D02 Port=3D03 Cnt=3D03 Dev#=3D  9 Spd=3D12   Mx=
Ch=3D 0
D:  Ver=3D 2.00 Cls=3Dff(vend.) Sub=3D01 Prot=3D01 MxPS=3D64 #Cfgs=3D  1
P:  Vendor=3D0a5c ProdID=3D21e6 Rev=3D 1.12
S:  Manufacturer=3DBroadcom Corp
S:  Product=3DBCM20702A0
S:  SerialNumber=3DF82FA8E8CFC0
C:* #Ifs=3D 4 Cfg#=3D 1 Atr=3De0 MxPwr=3D  0mA
I:* If#=3D 0 Alt=3D 0 #EPs=3D 3 Cls=3Dff(vend.) Sub=3D01 Prot=3D01 Driver=
=3Dbtusb
E:  Ad=3D81(I) Atr=3D03(Int.) MxPS=3D  16 Ivl=3D1ms
E:  Ad=3D82(I) Atr=3D02(Bulk) MxPS=3D  64 Ivl=3D0ms
E:  Ad=3D02(O) Atr=3D02(Bulk) MxPS=3D  64 Ivl=3D0ms
I:* If#=3D 1 Alt=3D 0 #EPs=3D 2 Cls=3Dff(vend.) Sub=3D01 Prot=3D01 Driver=
=3Dbtusb
E:  Ad=3D83(I) Atr=3D01(Isoc) MxPS=3D   0 Ivl=3D1ms
E:  Ad=3D03(O) Atr=3D01(Isoc) MxPS=3D   0 Ivl=3D1ms
I:  If#=3D 1 Alt=3D 1 #EPs=3D 2 Cls=3Dff(vend.) Sub=3D01 Prot=3D01 Driver=
=3Dbtusb
E:  Ad=3D83(I) Atr=3D01(Isoc) MxPS=3D   9 Ivl=3D1ms
E:  Ad=3D03(O) Atr=3D01(Isoc) MxPS=3D   9 Ivl=3D1ms
I:  If#=3D 1 Alt=3D 2 #EPs=3D 2 Cls=3Dff(vend.) Sub=3D01 Prot=3D01 Driver=
=3Dbtusb
E:  Ad=3D83(I) Atr=3D01(Isoc) MxPS=3D  17 Ivl=3D1ms
E:  Ad=3D03(O) Atr=3D01(Isoc) MxPS=3D  17 Ivl=3D1ms
I:  If#=3D 1 Alt=3D 3 #EPs=3D 2 Cls=3Dff(vend.) Sub=3D01 Prot=3D01 Driver=
=3Dbtusb
E:  Ad=3D83(I) Atr=3D01(Isoc) MxPS=3D  25 Ivl=3D1ms
E:  Ad=3D03(O) Atr=3D01(Isoc) MxPS=3D  25 Ivl=3D1ms
I:  If#=3D 1 Alt=3D 4 #EPs=3D 2 Cls=3Dff(vend.) Sub=3D01 Prot=3D01 Driver=
=3Dbtusb
E:  Ad=3D83(I) Atr=3D01(Isoc) MxPS=3D  33 Ivl=3D1ms
E:  Ad=3D03(O) Atr=3D01(Isoc) MxPS=3D  33 Ivl=3D1ms
I:  If#=3D 1 Alt=3D 5 #EPs=3D 2 Cls=3Dff(vend.) Sub=3D01 Prot=3D01 Driver=
=3Dbtusb
E:  Ad=3D83(I) Atr=3D01(Isoc) MxPS=3D  49 Ivl=3D1ms
E:  Ad=3D03(O) Atr=3D01(Isoc) MxPS=3D  49 Ivl=3D1ms
I:* If#=3D 2 Alt=3D 0 #EPs=3D 2 Cls=3Dff(vend.) Sub=3Dff Prot=3Dff Driver=
=3Dbtusb
E:  Ad=3D84(I) Atr=3D02(Bulk) MxPS=3D  32 Ivl=3D0ms
E:  Ad=3D04(O) Atr=3D02(Bulk) MxPS=3D  32 Ivl=3D0ms
I:* If#=3D 3 Alt=3D 0 #EPs=3D 0 Cls=3Dfe(app. ) Sub=3D01 Prot=3D01 Driver=
=3D(none)

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Szymon Janc <szymon.janc@codecoup.pl>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
 net/bluetooth/hci_core.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 3ac89e9ace71..4bd72d2fe415 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -548,6 +548,7 @@ static void hci_set_event_mask_page_2(struct hci_reques=
t *req)
 {
 	struct hci_dev *hdev =3D req->hdev;
 	u8 events[8] =3D { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
+	bool changed =3D false;
=20
 	/* If Connectionless Slave Broadcast master role is supported
 	 * enable all necessary events for it.
@@ -557,6 +558,7 @@ static void hci_set_event_mask_page_2(struct hci_reques=
t *req)
 		events[1] |=3D 0x80;	/* Synchronization Train Complete */
 		events[2] |=3D 0x10;	/* Slave Page Response Timeout */
 		events[2] |=3D 0x20;	/* CSB Channel Map Change */
+		changed =3D true;
 	}
=20
 	/* If Connectionless Slave Broadcast slave role is supported
@@ -567,13 +569,24 @@ static void hci_set_event_mask_page_2(struct hci_requ=
est *req)
 		events[2] |=3D 0x02;	/* CSB Receive */
 		events[2] |=3D 0x04;	/* CSB Timeout */
 		events[2] |=3D 0x08;	/* Truncated Page Complete */
+		changed =3D true;
 	}
=20
 	/* Enable Authenticated Payload Timeout Expired event if supported */
-	if (lmp_ping_capable(hdev) || hdev->le_features[0] & HCI_LE_PING)
+	if (lmp_ping_capable(hdev) || hdev->le_features[0] & HCI_LE_PING) {
 		events[2] |=3D 0x80;
+		changed =3D true;
+	}
=20
-	hci_req_add(req, HCI_OP_SET_EVENT_MASK_PAGE_2, sizeof(events), events);
+	/* Some Broadcom based controllers indicate support for Set Event
+	 * Mask Page 2 command, but then actually do not support it. Since
+	 * the default value is all bits set to zero, the command is only
+	 * required if the event mask has to be changed. In case no change
+	 * to the event mask is needed, skip this command.
+	 */
+	if (changed)
+		hci_req_add(req, HCI_OP_SET_EVENT_MASK_PAGE_2,
+			    sizeof(events), events);
 }
=20
 static int hci_init3_req(struct hci_request *req, unsigned long opt)
--=20
2.15.1