Hi Luiz,
>>>>> This introduces HCI_CONN_FLAG_DEVICE_PRIVACY which can be used by
>>>>> userspace to indicate to the controller to use Device Privacy Mode to a
>>>>> specific device.
>>>>>
>>>>> Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@xxxxxxxxx>
>>>>> ---
>>>>> v2: Fix marking Device Privacy Flag even when adapter is not capable of
>>>>> handling Set Privacy Mode.
>>>>>
>>>>> include/net/bluetooth/hci_core.h | 4 ++++
>>>>> net/bluetooth/mgmt.c | 24 ++++++++++++++++++++----
>>>>> 2 files changed, 24 insertions(+), 4 deletions(-)
>>>>>
>>>>> diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
>>>>> index b5f061882c10..07d2d099dc2a 100644
>>>>> --- a/include/net/bluetooth/hci_core.h
>>>>> +++ b/include/net/bluetooth/hci_core.h
>>>>> @@ -160,6 +160,7 @@ struct bdaddr_list_with_flags {
>>>>>
>>>>> enum hci_conn_flags {
>>>>> HCI_CONN_FLAG_REMOTE_WAKEUP,
>>>>> + HCI_CONN_FLAG_DEVICE_PRIVACY,
>>>>> HCI_CONN_FLAG_MAX
>>>>> };
>>>>>
>>>>> @@ -1468,6 +1469,9 @@ void hci_conn_del_sysfs(struct hci_conn *conn);
>>>>> #define use_ll_privacy(dev) (ll_privacy_capable(dev) && \
>>>>> hci_dev_test_flag(dev, HCI_ENABLE_LL_PRIVACY))
>>>>>
>>>>> +#define privacy_mode_capable(dev) (use_ll_privacy(dev) && \
>>>>> + (hdev->commands[39] & 0x04))
>>>>> +
>>>>> /* Use enhanced synchronous connection if command is supported */
>>>>> #define enhanced_sco_capable(dev) ((dev)->commands[29] & 0x08)
>>>>>
>>>>> diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
>>>>> index 06384d761928..8a8376d32be3 100644
>>>>> --- a/net/bluetooth/mgmt.c
>>>>> +++ b/net/bluetooth/mgmt.c
>>>>> @@ -4350,7 +4350,16 @@ static int set_exp_feature(struct sock *sk, struct hci_dev *hdev,
>>>>> MGMT_STATUS_NOT_SUPPORTED);
>>>>> }
>>>>>
>>>>> -#define SUPPORTED_DEVICE_FLAGS() ((1U << HCI_CONN_FLAG_MAX) - 1)
>>>>> +static u32 supported_device_flags(struct hci_dev *hdev)
>>>>> +{
>>>>> + u32 flags = BIT(HCI_CONN_FLAG_MAX) - 1;
>>>>> +
>>>>> + /* Check if Privacy Mode can be set */
>>>>> + if (!privacy_mode_capable(hdev))
>>>>> + flags &= ~BIT(HCI_CONN_FLAG_DEVICE_PRIVACY);
>>>>> +
>>>>> + return flags;
>>>>> +}
>>>>
>>>> I am lost on what we are doing, I know that SUPPORTED_DEVICE_FLAGS was introduced by 4c54bf2b093bb from Abhishek, but I fail to reason now why it is correct.
>>>
>>> But we don't set the HCI_CONN_FLAG_DEVICE_PRIVACY is hdev is not
>>> capable of setting it, anyway the general idea of the supported_flags
>>> is to indicate to userspace what flags the kernel is capable of
>>> settings, so yeah I would expected it to be capable of setting every
>>> flag except for those the controller don't have proper support for.
>>> Maybe you got confused by the logic of first enabling everything and
>>> then toggle back the bits that are not supported by the hdev.
>>
>> and I think that is wrong. We should only set the bits that the hardware and/or kernel supports. I have no idea on how I missed this in the review back then. I am trying to figure it out, but I am failing to follow this logic.
>
> There is only 1 flag currently though, HCI_CONN_FLAG_REMOTE_WAKEUP, so
> I wonder if that really requires a check? Or perhaps you want to
> change the way we supported_device_flags works to:
>
> index fe52b7eefb56..3ad09ce6eaeb 100644
> --- a/net/bluetooth/mgmt.c
> +++ b/net/bluetooth/mgmt.c
> @@ -4351,11 +4351,15 @@ static int set_exp_feature(struct sock *sk,
> struct hci_dev *hdev,
>
> static u32 supported_device_flags(struct hci_dev *hdev)
> {
> - u32 flags = BIT(HCI_CONN_FLAG_MAX) - 1;
> + u32 flags = 0;
> +
> + /* Check if adapter can wakeup the system */
> + if (hdev->wakeup && hdev->wakeup(hdev))
> + flags |= HCI_CONN_FLAG_REMOTE_WAKEUP;
>
> /* Check if Privacy Mode can be set */
> - if (!privacy_mode_capable(hdev))
> - flags &= ~BIT(HCI_CONN_FLAG_DEVICE_PRIVACY);
> + if (privacy_mode_capable(hdev))
> + flags |= HCI_CONN_FLAG_DEVICE_PRIVACY;
>
> return flags;
> }
yes, that is how I would expected it to be.
Regards
Marcel
