linux-kernel - Re: [PATCH v2 1/2] Bluetooth: Disable LE Advertising in hci_suspend

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Date:   Fri, 5 Jul 2019 14:58:27 +0800
From:   Kai-Heng Feng <kai.heng.feng@...onical.com>
To:     Marcel Holtmann <marcel@...tmann.org>,
        Johan Hedberg <johan.hedberg@...il.com>
Cc:     Linux Bluetooth mailing list <linux-bluetooth@...r.kernel.org>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 1/2] Bluetooth: Disable LE Advertising in
 hci_suspend_dev()

at 11:00, Kai Heng Feng <kai.heng.feng@...onical.com> wrote:

> Hi Marcel,
>
> at 5:25 PM, Kai-Heng Feng <kai.heng.feng@...onical.com> wrote:
>
>> LE Advertising may wake up system during system-wide sleep, disable it
>> to prevent this issue from happening.
>>
>> Do the reverse in hci_resume_dev().
>
> Do you have any suggestion for this patch?

Please let me know where I can do further improvement.

This can solve a hard freeze during system suspend.

Kai-Heng

>
> Kai-Heng
>
>> Signed-off-by: Kai-Heng Feng <kai.heng.feng@...onical.com>
>> ---
>> v2:
>> - Abstract away enabling/disabling LE advertising from btusb.
>>
>>  include/net/bluetooth/hci_core.h |  1 +
>>  net/bluetooth/hci_core.c         | 47 ++++++++++++++++++++++++++++++++
>>  2 files changed, 48 insertions(+)
>>
>> diff --git a/include/net/bluetooth/hci_core.h  
>> b/include/net/bluetooth/hci_core.h
>> index 094e61e07030..65574943131d 100644
>> --- a/include/net/bluetooth/hci_core.h
>> +++ b/include/net/bluetooth/hci_core.h
>> @@ -269,6 +269,7 @@ struct hci_dev {
>>  	__u16		le_max_rx_time;
>>  	__u8		le_max_key_size;
>>  	__u8		le_min_key_size;
>> +	__u8		le_events[8];
>>  	__u16		discov_interleaved_timeout;
>>  	__u16		conn_info_min_age;
>>  	__u16		conn_info_max_age;
>> diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
>> index d6b2540ba7f8..7c19e3b9294c 100644
>> --- a/net/bluetooth/hci_core.c
>> +++ b/net/bluetooth/hci_core.c
>> @@ -412,6 +412,49 @@ static void hci_setup_event_mask(struct hci_request  
>> *req)
>>  	hci_req_add(req, HCI_OP_SET_EVENT_MASK, sizeof(events), events);
>>  }
>>
>> +static int hci_enable_le_advertising_req(struct hci_request *req,  
>> unsigned long opt)
>> +{
>> +	struct hci_dev *hdev = req->hdev;
>> +	u8 events[8];
>> +	memcpy(events, hdev->le_events, sizeof(events));
>> +
>> +	hci_req_add(req, HCI_OP_LE_SET_EVENT_MASK, sizeof(events),
>> +			events);
>> +
>> +	return 0;
>> +}
>> +
>> +static int hci_disable_le_advertising_req(struct hci_request *req,  
>> unsigned long opt)
>> +{
>> +	struct hci_dev *hdev = req->hdev;
>> +
>> +	u8 events[8];
>> +	memcpy(events, hdev->le_events, sizeof(events));
>> +
>> +	events[0] &= ~(u8)0x02;	/* LE Advertising Report */
>> +
>> +	hci_req_add(req, HCI_OP_LE_SET_EVENT_MASK, sizeof(events),
>> +			events);
>> +
>> +	return 0;
>> +}
>> +
>> +static int hci_enable_le_advertising(struct hci_dev *hdev)
>> +{
>> +	if (!lmp_le_capable(hdev))
>> +		return 0;
>> +
>> +	return __hci_req_sync(hdev, hci_enable_le_advertising_req, 0,  
>> HCI_CMD_TIMEOUT, NULL);
>> +}
>> +
>> +static int hci_disable_le_advertising(struct hci_dev *hdev)
>> +{
>> +	if (!lmp_le_capable(hdev))
>> +		return 0;
>> +
>> +	return __hci_req_sync(hdev, hci_disable_le_advertising_req, 0,  
>> HCI_CMD_TIMEOUT, NULL);
>> +}
>> +
>>  static int hci_init2_req(struct hci_request *req, unsigned long opt)
>>  {
>>  	struct hci_dev *hdev = req->hdev;
>> @@ -772,6 +815,8 @@ static int hci_init3_req(struct hci_request *req,  
>> unsigned long opt)
>>  		}
>>
>>  		hci_set_le_support(req);
>> +
>> +		memcpy(hdev->le_events, events, sizeof(events));
>>  	}
>>
>>  	/* Read features beyond page 1 if available */
>> @@ -3431,6 +3476,7 @@ EXPORT_SYMBOL(hci_unregister_dev);
>>  /* Suspend HCI device */
>>  int hci_suspend_dev(struct hci_dev *hdev)
>>  {
>> +	hci_disable_le_advertising(hdev);
>>  	hci_sock_dev_event(hdev, HCI_DEV_SUSPEND);
>>  	return 0;
>>  }
>> @@ -3440,6 +3486,7 @@ EXPORT_SYMBOL(hci_suspend_dev);
>>  int hci_resume_dev(struct hci_dev *hdev)
>>  {
>>  	hci_sock_dev_event(hdev, HCI_DEV_RESUME);
>> +	hci_enable_le_advertising(hdev);
>>  	return 0;
>>  }
>>  EXPORT_SYMBOL(hci_resume_dev);
>> -- 
>> 2.17.1