IBSS support in ath10k - our test results and questions

[Simon Wunderlich]

Hi ath10k devs,

since there has been quite a bit of progress on IBSS in ath10k, we've been 
trying to integrate it into our OpenWRT based firmware and test it. Since there 
seems to be many people interested, I'd like to share our status and also ask 
for comments and support on current issues:

 * Our test was based on Ben Greears firmware v 13, OpenWRT rev 44654 and 
various patches (see details below at [1])
 * We can set up IBSS networks without problems, at least without IBSS/RSN 
encryption
 * AP+IBSS simultaneously works somewhat, but with quirks
 * We see low throughput when communicating via IBSS between 2x ath10k or 1x 
ath9k + 1x ath10k (~30 MiBit/s). With HT we would have expected ~150 MBit/s, 
with VHT even more.
 * We tracked down the reason to be aggregation not working - ath10k never 
sends ADDBA, and also does not respond to ADDBAs sent by ath9k
 * Aggregation works just fine in AP mode in ath10k

Therefore, I'd like to know if anyone has experience with Bens firmware and 
IBSS mode and can point us to existing issues/fixes, or recommend versions to 
test which are supposed to work. We had to add various VHT patches by hand, so 
we wonder if anyone had success with that yet, but even the HT performance is 
far from satisfactory.

Note that we also tried firmware 999.999.0.636 firmware and got better 
performance (70-90 MBit/s), but since it does not properly support AP it's not 
an option for us.

There are also a few other issues (IBSS/RSN not working - ath10k firmware does 
not seem to support software encryption properly ; IBSS+AP has spurious AP 
issues with a lot of packetloss), but that would be a topic for another time. 
Maybe we are just missing the right versions here ... :)

Thanks!!
    Simon



[1] Our components and software versions:
 * the devices were ath9k 2x2 (HT40), ath10k 2x2 (VHT80)
 * Ben Greears firmware 13 (all variants)
 * OpenWrt 44654
 * all ath10k patches between f3660a25c4ff15c10c197930b5e039311a25b477
   (master-2014-11-04) and v3.19
 * patches from git://dmz2.candelatech.com/linux-3.19.dev.y starting with
   3.19 and ending at lf-5.3.1 (patches for NFS, PCI, igb, ARM, hwmon,
   configs, ath9k, neigh, cifs, aesni, hwsim and vlan were dropped)
 * some patches to work around build errors in Ben Greears patches
 * a revert of "ath10k: Request OTP to return debug code." because it didn't
   work with his firmware on the target platform
 * patch "cfg80211: add extensible feature flag attribute"
 * patch "cfg80211: add VHT support for IBSS"
 * patch "mac80211: IBSS fix scan request"
 * Revert "mac80211: notify NSS changed when IBSS and HT"
   (required to update to the latest available patch)
 * "mac80211: notify NSS changed when IBSS and HT"
   (from http://mid.gmane.org/1418806852-558-1-git-send-email-janusz.dziedzic@tieto.com )

Most likely not relevant because it is just for the VHT support in IBSS
and the problem was already there before adding these patches

 * "mac80211: ibss refactor ieee80211_rx_bss_info"
 * "mac80211: tdls: disentangle HT supported conditions"
 * "mac80211: TDLS: support VHT between peers"
 * "mac80211: add VHT support for IBSS"
 * a patch to synchronize include/uapi/linux/nl80211.h with the version
   shipped by iw from OpenWrt 44654
 * a patch in ath10k to enable NL80211_EXT_FEATURE_VHT_IBSS
 * a patch to disable SMPS STATIC to get multiple chains HT MCS rates
   when communicating with ath9k
 * a patch to set a VHT channel when using "ibss join"
 * some patches to test things like encryption, trace wmi, ...
 * some patches to automatically install the CT community firmware using
   OpenWrt