Hi Marcel, On Wed, Oct 23, 2013, Marcel Holtmann wrote: > There is an old Panasonic module with a Zeevo chip in there that is > not really operating according to Bluetooth core specification when > it comes to setting the IAC LAP for limited discoverable mode. > > For reference, this is the vendor information about this module: > > < HCI Command: Read Local Version Information (0x04|0x0001) plen 0 > > HCI Event: Command Complete (0x0e) plen 12 > Read Local Version Information (0x04|0x0001) ncmd 1 > Status: Success (0x00) > HCI version: Bluetooth 1.2 (0x02) - Revision 196 (0x00c4) > LMP version: Bluetooth 1.2 (0x02) - Subversion 61 (0x003d) > Manufacturer: Zeevo, Inc. (18) > > The module reports only the support for one IAC at a time. And that > is totally acceptable according to the Bluetooth core specification > since the minimum supported IAC is only one. > > < HCI Command: Read Number of Supported IAC (0x03|0x0038) plen 0 > > HCI Event: Command Complete (0x0e) plen 5 > Read Number of Supported IAC (0x03|0x0038) ncmd 1 > Status: Success (0x00) > Number of IAC: 1 > > The problem arises when trying to program two IAC into the module > on a controller that only supports one. > > < HCI Command: Write Current IAC LAP (0x03|0x003a) plen 7 > Number of IAC: 2 > Access code: 0x9e8b00 (Limited Inquiry) > Access code: 0x9e8b33 (General Inquiry) > > HCI Event: Command Status (0x0f) plen 4 > Write Current IAC LAP (0x03|0x003a) ncmd 1 > Status: Unknown HCI Command (0x01) > > While this looks strange, but according to the Bluetooth core > specification it is a legal operation. The controller has to > ignore the other values and only program as many as it supports. > > This command shall clear any existing IACs and stores Num_Current_IAC > and the IAC_LAPs in to the controller. If Num_Current_IAC is greater > than Num_Support_IAC then only the first Num_Support_IAC shall be > stored in the controller, and a Command Complete event with error > code Success (0x00) shall be generated. > > This specific controller has a bug here and just returns an error. So > in case the number of supported IAC is less than two and the limited > discoverable mode is requested, now only the LIAC is written to > the controller. > > < HCI Command: Write Current IAC LAP (0x03|0x003a) plen 4 > Number of IAC: 1 > Access code: 0x9e8b00 (Limited Inquiry) > > HCI Event: Command Complete (0x0e) plen 4 > Write Current IAC LAP (0x03|0x003a) ncmd 1 > Status: Success (0x00) > > All other controllers that only support one IAC seem to handle this > perfectly fine, but this fix will only write the LIAC for these > controllers as well. > > Signed-off-by: Marcel Holtmann <marcel@xxxxxxxxxxxx> > --- > net/bluetooth/mgmt.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) Applied to bluetooth-next. Thanks. Johan -- To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
