Unable to set my channel with hostapd

[Krishna Chaitanya]

On Mon, Apr 29, 2013 at 2:59 PM, Francisco Cuesta <ndarkness at gmail.com> wrote:
>
> By the way, is there any function in hostapd that maps the frequency
> to channels and channels to frequency? if so, could anyone tell me
> where they're located?
>
> thanks in advance!
>
> 2013/4/29 Francisco Cuesta <ndarkness at gmail.com>:
> > Hi Luciano,
> >
> > Thanks in advance,
> >
> > I have modified my regulatory data base for USA in order to be able to
> > use that channel
> >
> >  iw reg get
> > country US:
> >     (2412 - 2484 @ 40), (3, 27)
> >     (4400 - 4940 @ 40), (N/A, 31)
> >     (4910 - 4990 @ 20), (N/A, 31)
> >     (5170 - 5250 @ 40), (N/A, 31)
> >     (5250 - 5330 @ 40), (N/A, 31), DFS
> >     (5490 - 5600 @ 40), (N/A, 31), DFS
> >     (5650 - 5710 @ 40), (N/A, 31), DFS
> >     (5735 - 6480 @ 40), (N/A, 31)
> >
> > But even though, I was getting the same error, do you have another good idea?
> >
> > thanks again!
> >
> >
> >
> >
> > 2013/4/29 Luciano Coelho <coelho at ti.com>:
> >> On Mon, 2013-04-29 at 12:01 +0300, Luciano Coelho wrote:
> >>> Hi Francisco,
> >>>
> >>> On Mon, 2013-04-29 at 10:27 +0200, Francisco Cuesta wrote:
> >>> > Hello,  thanks for replying,
> >>> >
> >>> > I'm using ath9k driver in openwrt with hostapd v2.0-devel.
> >>> >
> >>> > iw reg get
> >>> >     (2412 - 2472 @ 40), (3, 27)
> >>> >     (5170 - 5250 @ 40), (N/A, 31)
> >>> >     (5250 - 5330 @ 40), (N/A, 31), DFS
> >>> >     (5490 - 5600 @ 40), (N/A, 31), DFS
> >>> >     (5650 - 5710 @ 40), (N/A, 31), DFS
> >>>
> >>> Here you can see that the channel you want to use is not allowed by the
> >>> regulatory code.  It seems that you're using "00" as the country
> >>> (world).  From the regulatory database [1], you can see that channel 196
> >>> (4980 MHz) is only allowed in Japan (regulatory country "JP").
> >>
> >> Forgot to paste the link to the regulatory database:
> >>
> >> http://git.kernel.org/cgit/linux/kernel/git/linville/wireless-regdb.git/tree/db.txt
> >>
> >>>
> >>> > iw list
> >>> >
> >>> > Frequencies:
> >>> >             * 5180 MHz [36] (17.0 dBm)
> >>> >             * 5200 MHz [40] (21.0 dBm)
> >>> >             * 5220 MHz [44] (17.0 dBm)
> >>> >             * 5240 MHz [48] (17.0 dBm)
> >>> >             * 5260 MHz [52] (17.0 dBm) (radar detection)
> >>> >             * 5280 MHz [56] (17.0 dBm) (radar detection)
> >>> >             * 5300 MHz [60] (17.0 dBm) (radar detection)
> >>> >             * 5320 MHz [64] (17.0 dBm) (radar detection)
> >>> >             * 5500 MHz [100] (17.0 dBm) (radar detection)
> >>> >             * 5520 MHz [104] (21.0 dBm) (radar detection)
> >>> >             * 5540 MHz [108] (21.0 dBm) (radar detection)
> >>> >             * 5560 MHz [112] (21.0 dBm) (radar detection)
> >>> >             * 5580 MHz [116] (21.0 dBm) (radar detection)
> >>> >             * 5600 MHz [120] (disabled)
> >>> >             * 5620 MHz [124] (disabled)
> >>> >             * 5640 MHz [128] (disabled)
> >>> >             * 5660 MHz [132] (17.0 dBm) (radar detection)
> >>> >             * 5680 MHz [136] (17.0 dBm) (radar detection)
> >>> >             * 5700 MHz [140] (17.0 dBm) (radar detection)
> >>> >             * 5745 MHz [149] (21.0 dBm)
> >>> >             * 5765 MHz [153] (21.0 dBm)
> >>> >             * 5785 MHz [157] (21.0 dBm)
> >>> >             * 5805 MHz [161] (21.0 dBm)
> >>> >             * 5825 MHz [165] (20.0 dBm)
> >>> >             * 4915 MHz [183] (21.0 dBm)
> >>> >             * 4920 MHz [184] (21.0 dBm)
> >>> >             * 4925 MHz [185] (21.0 dBm)
> >>> >             * 4930 MHz [186] (21.0 dBm)
> >>> >             * 4935 MHz [187] (21.0 dBm)
> >>> >             * 4940 MHz [188] (21.0 dBm)
> >>> >             * 4945 MHz [189] (21.0 dBm)
> >>> >             * 4960 MHz [192] (21.0 dBm)
> >>> >             * 4980 MHz [196] (21.0 dBm)
> >>>
> >>> This shows that the driver supports 4980, but it won't be able to use it
> >>> if the regulatory doesn't allow it.
> >>>
> >>>
> >>> > But, could you explain me the reason behing I get this error, I mean,
> >>> > what does it mean, for instance  problem with the interface, the
> >>> > channel isn't supported by the driver ..., I would like to understand
> >>> > it, not just resolve it.
> >>>
> >>> This is because the radio regulations in the country you're choosing
> >>> ("world" is a set of frequencies that is valid in *every* country)
> >>> doesn't allow WiFi operation on the channel you want to use.  You can
> >>> only legally use channel 196 in Japan.  So, if you are in Japan, you can
> >>> do this:
>

As said earlier, Channel config is not only controlled by hostapd but also
 cfg80211 and driver.so if you can share the dmesg, then we can see why
the driver/cfg80211 has disabled that particular channel even though
its supported.