On 09/24/2014 11:23 PM, Michal Kazior wrote:
On 24 September 2014 18:30, Ben Greear <[email protected]> wrote:
On 09/24/2014 08:05 AM, Michal Kazior wrote:
On 24 September 2014 16:35, Ben Greear <[email protected]> wrote:
On 09/24/2014 12:51 AM, Michal Kazior wrote:
On 24 September 2014 02:26,  <[email protected]> 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.

I was thinking we might want to re-register someday, like after loading
a new firmware, or tuning firmware differently so that the vdev limits
changed.

If you are sure we currently only register once per module load, then
I agree that use_cfg_chains should not be needed currently.

But, considering my desire to allow to re-register in the future, I'd
prefer the patch to remain as is unless you disagree.

Thanks,
Ben



MichaƂ


--
Ben Greear <[email protected]>
Candela Technologies Inc  http://www.candelatech.com

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