Re: compat-wireless and minstrel

[Adam Wozniak <awozniak@irobot.com>]

Is it possible this is the problem? (note supp_rates is used at the 
bottom of the function, outside the "if")

*** a/net/mac80211/ibss.c    2009-11-02 09:11:36.000000000 -0800
--- b/net/mac80211/ibss.c    2009-11-10 16:31:46.291563951 -0800
***************
*** 246,254 ****
      if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
          return;
 
      if (sdata->vif.type == NL80211_IFTYPE_ADHOC && elems->supp_rates &&
          memcmp(mgmt->bssid, sdata->u.ibss.bssid, ETH_ALEN) == 0) {
-         supp_rates = ieee80211_sta_get_rates(local, elems, band);
 
          rcu_read_lock();
 
--- 246,255 ----
      if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
          return;
 
+     supp_rates = ieee80211_sta_get_rates(local, elems, band);
+
      if (sdata->vif.type == NL80211_IFTYPE_ADHOC && elems->supp_rates &&
          memcmp(mgmt->bssid, sdata->u.ibss.bssid, ETH_ALEN) == 0) {
 
          rcu_read_lock();
 


Derek Smithies wrote:
> Hi,
>> Do you know which frames in the mac80211 code are missing this 
>> required information?  Or was that conjecture?
>
> it was mostly conjecture. I had done some work with an earlier pull of 
> compat wireless in adhoc. the rates tried by minstrel were bad - it 
> was stuck at the slowest rate.
>
> I too had found that the fix was to adjust the array so that all rates 
> were marked as supported.
>
> Derek
>
> On Tue, 10 Nov 2009, Adam Wozniak wrote:
>
>> Reading through the 802.11 spec, it appears to me that "Supported 
>> rates" (and "Extended Supported Rates" when number of rates > 8) is 
>> REQUIRED for all management frames except authentication, 
>> deauthentication, and action frames. (IEEE 802.11-2007, 7.2.3)
>>
>> Do you know which frames in the mac80211 code are missing this 
>> required information?  Or was that conjecture?
>>
>> Looking at mac80211/tx.c ieee80211_beacon_get_tim, it is not clear to 
>> me how (or if) this rate information is being set for ad-hoc beacons.
>>
>> Derek Smithies wrote:
>>> Some management frames don't contain a full report of the rates 
>>> supported by the sender.
>>> My view is that node A (in this example) is incorrectly determining 
>>> that B only supports the 1mb/sec rate. Consequently, node A fills 
>>> the rate_supported  array with one rate - 1mb/sec.
>>
>>
>>
>