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From: Krishna Chaitanya <chaitanya.mgit@gmail.com>
Date: Sun, 25 May 2014 23:25:37 +0530
Message-ID: <CABPxzYK2xZwwQ4h+ifB6KP9wyr39RF2Z6zrsyZ=0CtC+YceRWQ@mail.gmail.com> (sfid-20140525_195711_974718_C296AF68)
Subject: Re: max_erip/tx_power not being set correctly
To: John Walker <john@x109.net>
Cc: linux-wireless <linux-wireless@vger.kernel.org>
Content-Type: text/plain; charset=UTF-8
Sender: linux-wireless-owner@vger.kernel.org

On Sat, May 24, 2014 at 6:04 PM, John Walker <john@x109.net> wrote:
>
> Hi Wireless Development
>
> I hope you can help.A bug seems to have been introduced in 3.10.34ish
> (3.10.32 is ok) linux kernel where a statically compiled regulator
> db.txt file does not set max_erip /tx_power correctly.
>
> It was first noticed that the power output of a RaspberyPi hostapd AP
> was only outputting -55dBm, while previously it was at -30dbm. This
> was measured with a phone app, wifi analyzer at 1 m distance.
>
> Any post 3.10.33 & late 3.12 kernels show the following when cfg80211
> is loaded. One can see that the max_erip is not set:
>
> cfg80211: Calling CRDA to update world regulatory domain
> cfg80211: World regulatory domain updated:
> cfg80211:   (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp)
> cfg80211:   (2402000 KHz - 2472000 KHz @ 0 KHz), (2000 mBi, 0 mBm)
> cfg80211:   (2457000 KHz - 2482000 KHz @ 0 KHz), (2000 mBi, 0 mBm)
> cfg80211:   (2474000 KHz - 2494000 KHz @ 20000 KHz), (2000 mBi, 0 mBm)
> cfg80211:   (5170000 KHz - 5250000 KHz @ 160000 KHz), (2000 mBi, 0 mBm)
> cfg80211:   (5250000 KHz - 5330000 KHz @ 160000 KHz), (2000 mBi, 0 mBm)
> cfg80211:   (5490000 KHz - 5730000 KHz @ 160000 KHz), (2000 mBi, 0 mBm)
> cfg80211:   (5735000 KHz - 5835000 KHz @ 80000 KHz), (2000 mBi, 0 mBm)
> cfg80211:   (57240000 KHz - 63720000 KHz @ 2160000 KHz), (N/A, 0 mBm)
> cfg80211: Calling CRDA for country: GB
> cfg80211: Regulatory domain changed to country: GB
> cfg80211:   (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp)
> cfg80211:   (2402000 KHz - 2482000 KHz @ 40000 KHz), (2000 mBi, 0 mBm)
> cfg80211:   (5170000 KHz - 5250000 KHz @ 80000 KHz), (2000 mBi, 0 mBm)
> cfg80211:   (5250000 KHz - 5330000 KHz @ 80000 KHz), (2000 mBi, 0 mBm)
> cfg80211:   (5490000 KHz - 5710000 KHz @ 80000 KHz), (2700 mBi, 0 mBm)
> cfg80211:   (57240000 KHz - 65880000 KHz @ 2160000 KHz), (4000 mBi, 0 mBm)
>
> iw list shows:
> [snip]
>     Frequencies:
>             * 2412 MHz [1] (0.0 dBm)
>             * 2417 MHz [2] (0.0 dBm)
>             * 2422 MHz [3] (0.0 dBm)
>             * 2427 MHz [4] (0.0 dBm)
>             * 2432 MHz [5] (0.0 dBm)
>             * 2437 MHz [6] (0.0 dBm)
>             * 2442 MHz [7] (0.0 dBm)
>             * 2447 MHz [8] (0.0 dBm)
>             * 2452 MHz [9] (0.0 dBm)
>             * 2457 MHz [10] (0.0 dBm)
>             * 2462 MHz [11] (0.0 dBm)
>             * 2467 MHz [12] (0.0 dBm)
>             * 2472 MHz [13] (0.0 dBm)
>             * 2484 MHz [14] (disabled)
>
> iw reg get shows:
> (3.12.20)
> country GB: DFS-UNSET
>     (2402 - 2482 @ 40), (20, 0)
>     (5170 - 5250 @ 80), (20, 0)
>     (5250 - 5330 @ 80), (20, 0)
>     (5490 - 5710 @ 80), (27, 0)
>     (57240 - 65880 @ 2160), (40, 0)
>
> When I've returned to a 3.10.32 kernel, the tx output power is
> restored to -30dBm, all the cfg80211 and iw list values are restored.
> I've also tested an old db.txt file from the start of the year against
> 3.12.19, but it makes no difference.
>
> iw list from 3.10.32
> [snip]
> Frequencies:
>             * 2412 MHz [1] (20.0 dBm)
>             * 2417 MHz [2] (20.0 dBm)
>             * 2422 MHz [3] (20.0 dBm)
>             * 2427 MHz [4] (20.0 dBm)
>             * 2432 MHz [5] (20.0 dBm)
>             * 2437 MHz [6] (20.0 dBm)
>             * 2442 MHz [7] (20.0 dBm)
>             * 2447 MHz [8] (20.0 dBm)
>             * 2452 MHz [9] (20.0 dBm)
>             * 2457 MHz [10] (20.0 dBm)
>             * 2462 MHz [11] (20.0 dBm)
>             * 2467 MHz [12] (20.0 dBm)
>             * 2472 MHz [13] (20.0 dBm)
>             * 2484 MHz [14] (disabled)
>
> iw reg get
> country GB: DFS-UNSET
>     (2402 - 2482 @ 40), (N/A, 20)
>     (5170 - 5250 @ 80), (N/A, 20)
>     (5250 - 5330 @ 80), (N/A, 20), DFS
>     (5490 - 5710 @ 80), (N/A, 27), DFS
>     (57240 - 65880 @ 2160), (N/A, 40), NO-OUTDOOR
>
>
> The iw version is 3.14
>
> I hope you can help, and many thanks
>


 This happens when we use the latest db.txt, its format is
changed. Please use the below patch from Luis.

https://dev.openwrt.org/browser/trunk/package/kernel/mac80211/patches/005-make-genregdb.awk-skip-antenna-gain.patch?rev=40296


-- 
Thanks,
Regards,
Chaitanya T K.