[rt2x00-users] 7 more packets after each beacon frame

[Helmut Schaa]

On Mon, Nov 14, 2011 at 3:51 PM, Ivo Van Doorn <ivdoorn at gmail.com> wrote:
> On Mon, Nov 14, 2011 at 3:44 PM, Helmut Schaa
> <helmut.schaa at googlemail.com> wrote:
>> On Mon, Nov 14, 2011 at 3:38 PM, Ivo Van Doorn <ivdoorn at gmail.com> wrote:
>>> Hi,
>>>
>>>>> Can't we just "program" the card with the right amount of BSSIDs as we
>>>>> need them?
>>>>> I.e. just set it to one at the start and change it later when more
>>>>> BSSIDs are added.
>>>>
>>>> Sure, would be possible but if we remove an interface that might leave
>>>> a hole in the beacon buffers. So, we would have to shift following
>>>> beacons such that we don't have holes between any beacons ...
>>>>
>>>> I'm just thinking about a way to implement this without much management
>>>> overhead.
>>>
>>> Another issue is that this solution will only reduce the number of extra
>>> beacons. Basically you can program the driver to have:
>>> 1, 2 or 8 beacons. So when you have 3 interfaces you will still have
>>> the extra beacons. Furthermore you have to change both the BSSID and
>>> unicode_to_me mask. And I am not sure if that will show any side effects.
>>
>> Hmm, not sure, we could just leave the MAC_BSSID_DW1_BSS_ID_MASK as "8"
>> and just initialize MAC_BSSID_DW1_BSS_BCN_NUM  with the actual number of
>> beaconing interfaces. I don't think the BSSID needs to have a specific value
>> depending on the used beacon slot ...
>>
>> So, I think it is possible but quite some changes are required.
>
> Yeah, especially since it means you have to constantly ensure that all enabled
> beacons are placed right after each other in the registers.. I would
> say that would
> add a lot of complexity which we don't want. So can we detect which drivers are
> broken and disable multi-BSSID for those?

I did some more testing with the ath9k_htc monitor and all my devices
suffer from
this issue :( I just didn't notice before because my intel monitor
device just dropped
all frames with invalid FCS.

Helmut