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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Jing Cai <jing.cai@mediatek.com>,
        Sean Wang <sean.wang@mediatek.com>,
        Luiz Augusto von Dentz <luiz.von.dentz@intel.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.19 223/717] Bluetooth: btusb: mediatek: fix WMT failure during runtime suspend
Date:   Sat, 22 Oct 2022 09:21:42 +0200
Message-Id: <20221022072454.584448188@linuxfoundation.org>
In-Reply-To: <20221022072415.034382448@linuxfoundation.org>
References: <20221022072415.034382448@linuxfoundation.org>
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From: Sean Wang <sean.wang@mediatek.com>

[ Upstream commit fd3f106677bac70437dc12e76c827294ed495a44 ]

WMT cmd/event doesn't follow up the generic HCI cmd/event handling, it
needs constantly polling control pipe until the host received the WMT
event, thus, we should require to specifically acquire PM counter on the
USB to prevent the interface from entering auto suspended while WMT
cmd/event in progress.

Fixes: a1c49c434e15 ("Bluetooth: btusb: Add protocol support for MediaTek MT7668U USB devices")
Co-developed-by: Jing Cai <jing.cai@mediatek.com>
Signed-off-by: Jing Cai <jing.cai@mediatek.com>
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/bluetooth/btusb.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
index aaba2d737178..6a320ece3276 100644
--- a/drivers/bluetooth/btusb.c
+++ b/drivers/bluetooth/btusb.c
@@ -2451,15 +2451,29 @@ static int btusb_mtk_hci_wmt_sync(struct hci_dev *hdev,
 
 	set_bit(BTUSB_TX_WAIT_VND_EVT, &data->flags);
 
+	/* WMT cmd/event doesn't follow up the generic HCI cmd/event handling,
+	 * it needs constantly polling control pipe until the host received the
+	 * WMT event, thus, we should require to specifically acquire PM counter
+	 * on the USB to prevent the interface from entering auto suspended
+	 * while WMT cmd/event in progress.
+	 */
+	err = usb_autopm_get_interface(data->intf);
+	if (err < 0)
+		goto err_free_wc;
+
 	err = __hci_cmd_send(hdev, 0xfc6f, hlen, wc);
 
 	if (err < 0) {
 		clear_bit(BTUSB_TX_WAIT_VND_EVT, &data->flags);
+		usb_autopm_put_interface(data->intf);
 		goto err_free_wc;
 	}
 
 	/* Submit control IN URB on demand to process the WMT event */
 	err = btusb_mtk_submit_wmt_recv_urb(hdev);
+
+	usb_autopm_put_interface(data->intf);
+
 	if (err < 0)
 		goto err_free_wc;
 
-- 
2.35.1