[PATCH] Bluetooth: btusb: request wake pin with NOAUTOEN

From: Brian Norris <briannorris@chromium.org>
To: Marcel Holtmann <marcel@holtmann.org>,
	Johan Hedberg <johan.hedberg@gmail.com>
Cc: linux-bluetooth@vger.kernel.org, <linux-kernel@vger.kernel.org>,
	Matthias Kaehlcke <mka@chromium.org>,
	Rajat Jain <rajatja@google.com>, Heiko Stuebner <heiko@sntech.de>,
	Brian Norris <briannorris@chromium.org>
Subject: [PATCH] Bluetooth: btusb: request wake pin with NOAUTOEN
Date: Thu, 21 Feb 2019 16:30:51 -0800	[thread overview]
Message-ID: <20190222003051.127006-1-briannorris@chromium.org> (raw)

Badly-designed systems might have (for example) active-high wake pins
that default to high (e.g., because of external pull ups) until they
have an active firmware which starts driving it low. This can cause an
interrupt storm in the time between request_irq() and disable_irq().

We don't support shared interrupts here, so let's just pre-configure the
interrupt to avoid auto-enabling it.

Fixes: fd913ef7ce61 ("Bluetooth: btusb: Add out-of-band wakeup support")
Signed-off-by: Brian Norris <briannorris@chromium.org>
---
 drivers/bluetooth/btusb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
index 4761499db9ee..470ee68555d9 100644
--- a/drivers/bluetooth/btusb.c
+++ b/drivers/bluetooth/btusb.c
@@ -2885,6 +2885,7 @@ static int btusb_config_oob_wake(struct hci_dev *hdev)
 		return 0;
 	}
 
+	irq_set_status_flags(irq, IRQ_NOAUTOEN);
 	ret = devm_request_irq(&hdev->dev, irq, btusb_oob_wake_handler,
 			       0, "OOB Wake-on-BT", data);
 	if (ret) {
@@ -2899,7 +2900,6 @@ static int btusb_config_oob_wake(struct hci_dev *hdev)
 	}
 
 	data->oob_wake_irq = irq;
-	disable_irq(irq);
 	bt_dev_info(hdev, "OOB Wake-on-BT configured at IRQ %u", irq);
 	return 0;
 }
-- 
2.21.0.rc0.258.g878e2cd30e-goog

