Return-Path: Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 11.5 \(3445.9.1\)) Subject: Re: [PATCH] Bluetooth: btusb: Add HCI reset command on BT shutdown From: Marcel Holtmann In-Reply-To: <1533104622-835-1-git-send-email-amit.k.bag@intel.com> Date: Wed, 1 Aug 2018 09:16:12 +0200 Cc: linux-bluetooth@vger.kernel.org, ravishankar.srivatsa@intel.com Message-Id: References: <1533104622-835-1-git-send-email-amit.k.bag@intel.com> To: Amit K Bag Sender: linux-bluetooth-owner@vger.kernel.org List-ID: Hi Amit, > In case of BT turn off from UI it is safe to add HCI reset command > which will maintain the controller state. this needs to be a bit more details since hdev->shutdown handling is really only for the older Intel controllers. Also I am failing to see why HCI Reset helps or what it does here. It is going to be called again on hdev->open the next time the controller is activated. > > Signed-off-by: Amit K Bag > --- > drivers/bluetooth/btusb.c | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c > index 572fd75fbcf6..599ec9b12d3f 100644 > --- a/drivers/bluetooth/btusb.c > +++ b/drivers/bluetooth/btusb.c > @@ -2369,6 +2369,18 @@ static int btusb_shutdown_intel(struct hci_dev *hdev) > struct sk_buff *skb; > long ret; > > + /* In case of BT off from UI it is safe to do HCI reset. > + * This will maintain the controller state. > + */ I do not care what the UI does here. This is power down operation and so it needs to be explained properly. And with a lot more details since I am failing to understand what state is maintained on HCI Reset. As per specification it will reset all Bluetooth states back to the defaults. > + skb = __hci_cmd_sync(hdev, HCI_OP_RESET, 0, NULL, HCI_INIT_TIMEOUT); > + if (IS_ERR(skb)) { > + ret = PTR_ERR(skb); > + BT_ERR("%s: BT controller HCI reset failed (%ld)", > + hdev->name, ret); > + return ret; > + } > + kfree_skb(skb); > + There is whitespace damage here. And if this hasn’t been done yet, please first start using bt_dev_err instead of BT_ERR for the Intel parts. > /* Some platforms have an issue with BT LED when the interface is > * down or BT radio is turned off, which takes 5 seconds to BT LED > * goes off. This command turns off the BT LED immediately. Regards Marcel