Cannot use 80MHz channel

Kalle Valo kvalo at
Wed Dec 18 01:59:19 EST 2013

Michal Kazior <michal.kazior at> writes:

> On 17 December 2013 22:51, Li Sun <lsun3 at> wrote:
>> Hi,
>> I am trying to play around with the ath10k driver. I have two Qualcomm
>> Atheros QCA9880 Version 2 802.11ac chipsets. I put one of the cards in
>> AP mode using hostapd and connect the other one as a client.
>> I am using the hostapd config mentioned at
>> "". The
>> client connects but the throughput is just around 300 Mbps (suggesting
>> 40 MHz channel-width) and NOT any higher. It seems I am unable to use
>> the 80 MHz channel-width. Also, when I checked the kernel logs
>> (dmesg), I found the following message on the client side only:
>> capabilities/regulatory prevented using AP HT/VHT configuration, downgraded
>> Could this problem be related to CRDA ? I am in the US.
> Check output of `iw reg get`. If you see no entries with `@ 80` you
> have to upgrade your regdb.

And the easiest way to do that (if you compile your own kernels) is to
enable CONFIG_CFG80211_INTERNAL_REGDB and copy db.txt from
wireless-regdb to net/wireless/db.txt.

Kalle Valo

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