vht_capab reading 0x0 but `iw list` says otherwise

[James Sumners]

Full config is below. If I understand the documentation[1] correctly, then
`hw_mode=g` implies the higher bands. But I must admit, it seems strange to
me that I don't need to set `hw_mode=ac` or something like `hw_mode=g,n,ac`.

```
interface=wlp4s0
bssid=02:5c:f8:0d:26:40
#bridge=br0
driver=nl80211

logger_syslog=-1
logger_syslog_level=2
logger_stdout=-1
logger_stdout_level=2

ctrl_interface=/var/run/hostapd
ctrl_interface_group=0

ssid=test
hw_mode=g
channel=4
country_code=US
ieee80211d=1
ieee80211h=1

beacon_int=100
dtim_period=2
max_num_sta=255
rts_threshold=1024
fragm_threshold=256
preamble=1

# Can't setup a second SSID since the wireles
# card only supports a single SSID
#bss=wlan_0
#ssid=ntest

### WMM settings ###
wmm_enabled=1
# Low priority / AC_BK = background
wmm_ac_bk_cwmin=4
wmm_ac_bk_cwmax=10
wmm_ac_bk_aifs=7
wmm_ac_bk_txop_limit=0
wmm_ac_bk_acm=0
# Note: for IEEE 802.11b mode: cWmin=5 cWmax=10
#
# Normal priority / AC_BE = best effort
wmm_ac_be_aifs=3
wmm_ac_be_cwmin=4
wmm_ac_be_cwmax=10
wmm_ac_be_txop_limit=0
wmm_ac_be_acm=0
# Note: for IEEE 802.11b mode: cWmin=5 cWmax=7
#
# High priority / AC_VI = video
wmm_ac_vi_aifs=2
wmm_ac_vi_cwmin=3
wmm_ac_vi_cwmax=4
wmm_ac_vi_txop_limit=94
wmm_ac_vi_acm=0
# Note: for IEEE 802.11b mode: cWmin=4 cWmax=5 txop_limit=188
#
# Highest priority / AC_VO = voice
wmm_ac_vo_aifs=2
wmm_ac_vo_cwmin=2
wmm_ac_vo_cwmax=3
wmm_ac_vo_txop_limit=47
wmm_ac_vo_acm=0
# Note: for IEEE 802.11b mode: cWmin=3 cWmax=4 burst=102


### 802.11n settings ###
ieee80211n=1
ht_capab=[HT40+][SMPS-STATIC][SHORT-GI-20][SHORT-GI-40][TX-STBC][RX-STBC1][DSSS_CCK-40]
obss_interval=5

### 802.11ac settings ###
ieee80211ac=1
#vht_capab=[SHORT-GI-80]
#vht_capab=[TX-STBC-2BY1][SU-BEAMFORMEE]
vht_oper_chwidth=0
vht_oper_centr_freq_seg0_idx=42
vht_oper_centr_freq_seg1_idx=159

### WPA2-PSK settings ###
wpa=2
wpa_passphrase=some nice and long passphrase
wpa_pairwise=CCMP
peerkey=1

### Time settings ###
time_advertisement=2
time_zone=EST5
```

[1] -- http://w1.fi/cgit/hostap/tree/hostapd/hostapd.conf#n128

On Wed, Oct 14, 2015 at 1:48 PM, Krishna Chaitanya <chaitanya.mgit at gmail.com
> wrote:

> On Wed, Oct 14, 2015 at 11:04 PM, James Sumners <james.sumners at gmail.com>
> wrote:
> >
> > When I launch hostapd I see a line in the log that reads "hw vht capab:
> > 0x0, conf vht capab: 0x0". That is accurate because I currently have no
> > `vht_capab` line defined in my configuration. However, if I do an `iw
> > list` on my device then I see the following list of capabilities:
> >
> > ```
> > VHT Capabilities (0x038071a0):
> >   Max MPDU length: 3895
> >   Supported Channel Width: neither 160 nor 80+80
> >   short GI (80 MHz)
> >   TX STBC
> >   SU Beamformee
> > VHT RX MCS set:
> >   1 streams: MCS 0-9
> >   2 streams: MCS 0-9
> >   4 streams: not supported
> >   ...
> >   8 streams: not supported
> > VHT RX highest supported: 0 Mbps
> > VHT TX MCS set:
> >   1 streams: MCS 0-9
> >   2 streams: MCS 0-9
> >   4 streams: not supported
> >   ...
> >   8 streams: not supported
> > VHT TX highest supported: 0 Mbps
> > ```
> >
> > When I set my hostapd config to have the line
> > `vht_capab=[SHORT-GI-80][TX-STBC-2BY1][SU-BEAMFORMEE]` then I get
> > an error that "SHORT-GI-80" is not supported. I can remove each
> > capability from the configuration directive and get the same sort of
> > result.
> >
> > When I set `vht_oper_chwidth=1`, without setting `vht_capab`, then I
> > get an error:
> >
> > ```
> > Mode: IEEE 802.11g Channel: 4 Frequency: 2427 MHz
> > DFS chan_idx seems wrong; num-ch: 13 ch-no: 36 conf-ch-no: 4 11n: 1
> > sec-ch: 0 vht-oper-width: 1
> > // list of channels available - [1, 13]
> > ```
> >
> > If I set `vht_oper_chwidth=0`, still without `vht_capab` set, then I
> > get an error:
> >
> > ```
> > Mode: IEEE 802.11g Channel: 4 Frequency: 2427 MHz
> > DFS 0 channels required radar detection
> > Could not set channel for kernel driver
> > ```
> >
> > If I set `ieee80211ac=0` then hostapd starts up correctly (no other
> > changes to the configuration).
> >
> > My card is an Intel 7260 that supports both AP and "AP/VLAN" modes with
> > one BSSID. I am using the nl80211 driver (i.e. `driver=nl80211` in
> > hostapd.conf).
> >
> > Do you have any suggestions as to what could be wrong with my setup?
> >
> It looks like you are trying to use VHT in 2.4GHz.
> Can you past the full config? is your hw_mode set to a to use VHT?
>



-- 
James Sumners
http://james.sumners.info/ (technical profile)
http://jrfom.com/ (personal site)
http://haplo.bandcamp.com/ (band page)
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.shmoo.com/pipermail/hostap/attachments/20151014/57cfe26e/attachment-0001.htm>