[BUG] QWLE900V5-18 - cannot achievie 3 spatial streams link

Kalle Valo kvalo at qca.qualcomm.com
Mon Dec 9 04:04:56 EST 2013

Janusz Dziedzic <janusz.dziedzic at tieto.com> writes:

> On 6 December 2013 17:33, Tomasz Tajmajer <tt at elnovel.com> wrote:
>> Hi,
>> Recently, I've been making quite a lot of tests with two QWLE900V5-18 cards.
>> I had some issues with the drivers (e.g. regarding the regulatory domain),
>> but I've managed to fix them on my own. However, there is one issue that I
>> cannot deal with.
>> I'm trying to get the highest throughput possible using 3x3 MIMO. The
>> problem is that the wifi card does not set higher rates than 2x433.3Mbps
>> (MCS 9, VHT-NSS 2). The specification says that it should be possible to
>> have 3 spatial streams.
>> First, I thought it is a problem with some options of hostapd, but hostapd
>> even does not allows me to set the [RX-STBC-12] or [RX-STBC-123] options.
>> Only [RX-STBC-1] may be set in the configuration (what in fact, does not
>> disallows the 2x433.3Mbps link, which is another issue).
>> Driver info shows that the driver should support 3 spatial streams.
>> I am not sure where is the problem, is it some bug in hostapd, which forces
>> the card to use 2 spatial streams only or is it the driver, which does not
>> enable 3 streams when it is possible. The physical connectivity (antennas
>> etc.) is not the problem AFAIK.
> When sta assoc to ap you will get dbg mesg (you can enable this eg.
> when loading ath10k_core module with param - debug_mask).
> "mac ht peer %pM mcs cnt %d nss %d\n" - nss is interesting here

This debug message is enabled with ATH10K_DBG_MAC. More info here:


> Also rx_mcs_set for STA from ath10k_peer_assoc_h_vht() could be
> interesting - unfortunetly we don't print this. But you can print
> this.

Indeed, we should include that to the message as well.

Kalle Valo

More information about the ath10k mailing list