Hi Marcel, Johan, On Sat, Dec 22, 2012 at 10:09 PM, Marcel Holtmann <marcel@xxxxxxxxxxxx> wrote: > Hi Johan, > >> > If we register a uuid other than uuid16, especially custom 128 bit uuid >> > then nothing is updated in the EIR and it was broken. >> > >> > After registering a 16 bit uuid. ex: "sdptool add SP", we can see the >> > uuid in the EIR as below. >> > < 0000: 01 52 0c f1 00 08 09 52 65 64 77 6f 6f 64 15 03 .R.....Redwood.. >> > 0010: 01 11 32 11 2f 11 06 11 05 11 0a 11 0e 11 0c 11 ..2./........... >> > 0020: 1f 11 12 11 00 00 00 00 00 00 00 00 00 00 00 00 ................ >> > 0030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ >> > 0040: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ >> > 0050: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ >> > 0060: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ >> > 0070: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ >> > 0080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ >> > 0090: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ >> > 00a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ >> > 00b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ >> > 00c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ >> > 00d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ >> > 00e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ >> > 00f0: 00 00 00 00 00 ..... >> > > 0000: 04 0e 04 01 52 0c 00 ....R.. >> > >> > But after register a user defined 128 bit uuid, nothing is >> > updated in the EIR. >> > >> > < 0000: 01 52 0c f1 00 08 09 52 65 64 77 6f 6f 64 00 00 .R.....Redwood.. >> > 0010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ >> > 0020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ >> > 0030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ >> > 0040: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ >> > 0050: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ >> > 0060: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ >> > 0070: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ >> > 0080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ >> > 0090: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ >> > 00a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ >> > 00b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ >> > 00c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ >> > 00d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ >> > 00e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ >> > 00f0: 00 00 00 00 00 ..... >> > > 0000: 04 0e 04 01 52 0c 00 ....R.. >> > >> > With this fix, we can see the EIR is updated properly. >> > >> > Signed-off-by: Syam Sidhardhan <s.syam@xxxxxxxxxxx> >> > --- >> > net/bluetooth/mgmt.c | 2 -- >> > 1 file changed, 2 deletions(-) >> > >> > diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c >> > index f559b96..512a3f5 100644 >> > --- a/net/bluetooth/mgmt.c >> > +++ b/net/bluetooth/mgmt.c >> > @@ -514,8 +514,6 @@ static void create_eir(struct hci_dev *hdev, u8 *data) >> > u16 uuid16; >> > >> > uuid16 = get_uuid16(uuid->uuid); >> > - if (uuid16 == 0) >> > - return; >> > >> > if (uuid16 < 0x1100) >> > continue; >> >> Nak. The bug is real and should be fixed but your fix is wrong. The >> right fix it to convert this return statement into a continue statement >> since we do still want to check for a 0 return value from get_uuid16. >> Since the next statements (uuid16 < 0x1100) indirectly do this logic, I intentionally removed it in order to avoid duplication. Probably for more clarity and readability, I can do it as per your suggestion. >> Along with this patch please prepare another one to increment the mgmt >> revision. These two should go together to upstream trees so that we can >> introduce a check in user space to know whether it's safe to pass >> non-16bit UUIDs to the kernel or not. > Ok. > I want a fix that introduces also support for 32-bit and 128-bit UUIDs > now. No paper over the hole fixing here. > As per the specification, "To reduce interference, the host should try to minimize the amount of EIR data such that the baseband can use a 1-slot or 3-slot EIR packet. This is advantageous because it reduces interference and maximizes the probability that the EIR packet will be received." Does the addition of 128-bit and 32-bit uuid decreases the probability of the reception of EIR packet, if any application register more of these types? Regards, Syam -- 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
