[RFC 2/2] ath10k: re-config ht_caps when chainmask is modified.

[Michal Kazior]

On 24 September 2014 18:30, Ben Greear <greearb at candelatech.com> wrote:
> On 09/24/2014 08:05 AM, Michal Kazior wrote:
>> On 24 September 2014 16:35, Ben Greear <greearb at candelatech.com> wrote:
>>> On 09/24/2014 12:51 AM, Michal Kazior wrote:
>>>> On 24 September 2014 02:26,  <greearb at candelatech.com> wrote:
>>>> [...]
>>>>>
>>>>> +static struct ieee80211_sta_vht_cap ath10k_create_vht_cap(struct ath10k
>>>>> *ar,
>>>>> +                                                         bool
>>>>> use_cfg_chains)
>>>>>   {
>>>>>          struct ieee80211_sta_vht_cap vht_cap = {0};
>>>>>          u16 mcs_map;
>>>>>          int i;
>>>>> +       int nrf = ar->num_rf_chains;
>>>>> +
>>>>> +       if (use_cfg_chains && ar->cfg_tx_chainmask)
>>>>> +               nrf = get_nss_from_chainmask(ar->cfg_tx_chainmask);
>>>>
>>>>
>>>> Is use_cfg_chains really necessary here? Is setting tx/rx chainmask to
>>>> 0x0 make any sense at all? Shouldn't we deny it or make it fallback to
>>>> the supported tx/rx chainmask values?
>>>
>>> It would cause the logic to flip back to the defaults, so seems mildly
>>> useful.  I'm not sure
>>> upper layers would ever let it be < 1 though.
>>
>> 0 is a valid argument as far as upper layers are concerned and should
>> be treated as "use all available antennas" (see `iw list` output
>> before ever setting antenna, after setting to, e.g. 1 and then to 0).
>>
>> This implies current set_antenna() implementation is actually buggy
>> (pdev param should involve using supp_tx/rx_chainmask). Your
>> assumption in recent patches is also incorrect as antenna mask = 0
>> should imply max nss, not 1.
>
> I tested this using:
>
> iw phy wiphy1 set antenna 0 0
>
> This flips it back to 3x3 (I had previously configured it for 2x2),
> so I think the patches are working properly.

Mea culpa. It will flip back indeed.

But I still don't see why use_cfg_chains is necessary. I don't see how
cfg_tx_chainmask could be non-zero when ath10k is registering to mac.


Michał