Re: [PATCH v2] Bluetooth: Fix incorrect ssp mode bit for non ssp devices

[Gustavo Padovan <gustavo@padovan.org>]

Hi Jaganath,

* Jaganath Kanakkassery <jaganath.k@samsung.com> [2013-04-09 11:41:42 +0530]:

> Some faulty non ssp devices send extended inquiry response
> during device discovery which is a violation of 2.1 specification.
> So for these devices we set ssp bit during acl connection
> initiation thinking that it is an ssp device. But for these
> devices, in remote extended features event ssp supported bit
> will be off. But we are not clearing the ssp bit in that case
> and eventually ssp bit in conn flag will be incorrectly set for
> these devices.
> 
> The software which has caused this issue is MecApp
> http://www.mecel.se/products/bluetooth/downloads/MecApp_download
> 
> This patch does a workaround by clearing the ssp bit if it is
> not supported in remote extended features event
> 
> hcidump log
> ----------
> 
> < HCI Command: Inquiry (0x01|0x0001) plen 5
>     lap 0x9e8b33 len 4 num 0
> > HCI Event: Command Status (0x0f) plen 4
>     Inquiry (0x01|0x0001) status 0x00 ncmd 1
> > HCI Event: Extended Inquiry Result (0x2f) plen 255
>     bdaddr 00:1B:DC:05:B5:25 mode 1 clkoffset 0x3263 class 0x3c0000 rssi -77
>     Unknown type 0x42 with 8 bytes data
>     Unknown type 0x1e with 2 bytes data
> > HCI Event: Inquiry Complete (0x01) plen 1
>     status 0x00
> 
> < HCI Command: Create Connection (0x01|0x0005) plen 13
>     bdaddr 00:1B:DC:05:B5:25 ptype 0xcc18 rswitch 0x01 clkoffset 0x0000
>     Packet type: DM1 DM3 DM5 DH1 DH3 DH5
> > HCI Event: Command Status (0x0f) plen 4
>     Create Connection (0x01|0x0005) status 0x00 ncmd 1
> > HCI Event: Connect Complete (0x03) plen 11
>     status 0x00 handle 12 bdaddr 00:1B:DC:05:B5:25 type ACL encrypt 0x00
> < HCI Command: Read Remote Supported Features (0x01|0x001b) plen 2
>     handle 12
> > HCI Event: Command Status (0x0f) plen 4
>     Read Remote Supported Features (0x01|0x001b) status 0x00 ncmd 1
> > HCI Event: Read Remote Supported Features (0x0b) plen 11
>     status 0x00 handle 12
>     Features: 0xff 0xff 0x8f 0x7e 0xd8 0x1f 0x5b 0x87
> < HCI Command: Read Remote Extended Features (0x01|0x001c) plen 3
>     handle 12 page 1
> > HCI Event: Command Status (0x0f) plen 4
>     Read Remote Extended Features (0x01|0x001c) status 0x00 ncmd 1
> > HCI Event: Page Scan Repetition Mode Change (0x20) plen 7
>     bdaddr 00:1B:DC:05:B5:25 mode 1
> > HCI Event: Max Slots Change (0x1b) plen 3
>     handle 12 slots 5
> > HCI Event: Read Remote Extended Features (0x23) plen 13
>     status 0x00 handle 12 page 1 max 0
>     Features: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
> < HCI Command: Remote Name Request (0x01|0x0019) plen 10
>     bdaddr 00:1B:DC:05:B5:25 mode 2 clkoffset 0x0000
> > HCI Event: Command Status (0x0f) plen 4
>     Remote Name Request (0x01|0x0019) status 0x00 ncmd 1
> > HCI Event: Remote Name Req Complete (0x07) plen 255
>     status 0x00 bdaddr 00:1B:DC:05:B5:25 name 'Bluetooth PTS Radio v4'
> < HCI Command: Authentication Requested (0x01|0x0011) plen 2
>     handle 12
> > HCI Event: Command Status (0x0f) plen 4
>     Authentication Requested (0x01|0x0011) status 0x00 ncmd 1
> > HCI Event: Link Key Request (0x17) plen 6
>     bdaddr 00:1B:DC:05:B5:25
> < HCI Command: Link Key Request Negative Reply (0x01|0x000c) plen 6
>     bdaddr 00:1B:DC:05:B5:25
> > HCI Event: Command Complete (0x0e) plen 10
>     Link Key Request Negative Reply (0x01|0x000c) ncmd 1
>     status 0x00 bdaddr 00:1B:DC:05:B5:25
> > HCI Event: PIN Code Request (0x16) plen 6
>     bdaddr 00:1B:DC:05:B5:25
> 
> Signed-off-by: Jaganath Kanakkassery <jaganath.k@samsung.com>
> ---
>  net/bluetooth/hci_event.c |    4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
> index 0a2b128..c1af186 100644
> --- a/net/bluetooth/hci_event.c
> +++ b/net/bluetooth/hci_event.c
> @@ -2935,6 +2935,10 @@ static void hci_remote_ext_features_evt(struct hci_dev *hdev,
>  
>  		if (ev->features[0] & LMP_HOST_SSP)
>  			set_bit(HCI_CONN_SSP_ENABLED, &conn->flags);
> +		else
> +			/* This is a workaround for some devices which send eir
> +			 * which actually does not support ssp */
> +			clear_bit(HCI_CONN_SSP_ENABLED, &conn->flags);

Since you added a comment after the else I would like to see braces both in
the if and else parts. Makes reading easier.

	Gustavo