Re: [PATCH] Bluetooth: Fix conditions for HCI_Delete_Stored_Link_Key

[Gustavo Padovan <gustavo@padovan.org>]

Hi Marcel,

* Marcel Holtmann <marcel@holtmann.org> [2013-06-13 12:34:09 +0200]:

> Hi Johan,
> 
> > Even though the HCI_Delete_Stored_Link_Key command is mandatory for 1.1
> > and later controllers some controllers do not seem to support it
> > properly as was witnessed by one Broadcom based controller:
> > 
> > < HCI Command: Delete Stored Link Key (0x03|0x0012) plen 7
> >    bdaddr 00:00:00:00:00:00 all 1
> >> HCI Event: Command Complete (0x0e) plen 4
> >    Delete Stored Link Key (0x03|0x0012) ncmd 1
> >    status 0x11 deleted 0
> >    Error: Unsupported Feature or Parameter Value
> > 
> > Luckily this same controller also doesn't list the command in its
> > supported commands bit mask (counting from 0 bit 7 of octet 6):
> > 
> > < HCI Command: Read Local Supported Commands (0x04|0x0002) plen 0
> >> HCI Event: Command Complete (0x0e) plen 68
> >    Read Local Supported Commands (0x04|0x0002) ncmd 1
> >    status 0x00
> >    Commands: ffffffffffff1ffffffffffff30fffff3f
> > 
> > Therefore, it makes sense to move sending of HCI_Delete_Stored_Link_Key
> > to after receiving the supported commands response and to only send it
> > if its respective bit in the mask is set. The downside of this is that
> > we no longer send the HCI_Delete_Stored_Link_Key command for Bluetooth
> > 1.1 controllers since HCI_Read_Local_Supported_Command was introduced in
> > version 1.2, but this is an acceptable penalty as the command in
> > question shouldn't affect critical behavior.
> > 
> > Reported-by: Pavel Machek <pavel@ucw.cz>
> > Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
> > ---
> > net/bluetooth/hci_core.c |   14 +++++++++-----
> > 1 file changed, 9 insertions(+), 5 deletions(-)
> > 
> > diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
> > index d817c93..d68425c 100644
> > --- a/net/bluetooth/hci_core.c
> > +++ b/net/bluetooth/hci_core.c
> > @@ -341,7 +341,6 @@ static void hci_init1_req(struct hci_request *req, unsigned long opt)
> > 
> > static void bredr_setup(struct hci_request *req)
> > {
> > -	struct hci_cp_delete_stored_link_key cp;
> > 	__le16 param;
> > 	__u8 flt_type;
> > 
> > @@ -365,10 +364,6 @@ static void bredr_setup(struct hci_request *req)
> > 	param = __constant_cpu_to_le16(0x7d00);
> > 	hci_req_add(req, HCI_OP_WRITE_CA_TIMEOUT, 2, &param);
> > 
> > -	bacpy(&cp.bdaddr, BDADDR_ANY);
> > -	cp.delete_all = 0x01;
> > -	hci_req_add(req, HCI_OP_DELETE_STORED_LINK_KEY, sizeof(cp), &cp);
> > -
> > 	/* Read page scan parameters */
> > 	if (req->hdev->hci_ver > BLUETOOTH_VER_1_1) {
> > 		hci_req_add(req, HCI_OP_READ_PAGE_SCAN_ACTIVITY, 0, NULL);
> > @@ -602,6 +597,15 @@ static void hci_init3_req(struct hci_request *req, unsigned long opt)
> > 	struct hci_dev *hdev = req->hdev;
> > 	u8 p;
> 
> I would have added here a comment to explain what bit we are checking for.

I just added:

/* Only send HCI_Delete_Stored_Link_Key if it is supported */

	Gustavo