[ath9k-devel] Strange reception problem with ar9285

[ath9k-devel] Strange reception problem with ar9285

[Holger Schurig]

I noticed a strange connection problem with an ar9285 PCIe card in one
location. I noticed that wpa_supplicant had connection problems. Then
I looked with "iw wlan0 scan" and found that I sometimes don't get
scan results, despite the fact that there are plenty of APs around
.... and despite the fact that devices with ath5k wireless card and my
Laptop with iwlwifi see them too.

Finally I tracked this down to some time-based reception problem. When
I enter these commands:

# make sure wpa_supplicant doesn't scan in the background (no NM running)
ifdown wlan0
iw wlan0 interface add mon0 type monitor
ifconfig mon0 up
iw mon0 set freq 2437
sleep 3
iw mon0 set freq 2412
tcpdump -i mon0

Now something strange happens: in the first few seconds, tcpdump
doesn't get packets, or only a few. Some ten seconds later, it get's a
good bunch of packets, but not yet the ~10 packets/s from one AP that
I'd expect. Some seconds later again I get everything.

While I keep tcpdump running and again change the frequency away and
back, the same happens. no packets, a few packets, full reception.


This weird behavior doesn't happen everywhere. I know 3 office places
where it doesn't happen, but one office place and one warehouse where
it happens. Oh, and BTW, it happened first with a kernel 3.2.16 from
kernel.org, then I tried it again with compat-wireless-2012-05-08.

Any ideas on how to debug this further?



-- 
http://www.holgerschurig.de

[ath9k-devel] Strange reception problem with ar9285

[Adrian Chadd]

Do you have both antennas connected?



Adrian

[ath9k-devel] Have a question

[Sunil Mehta]

Hi Adrian,

I have registered for the ath9k-devel, but could figure out how to post my
questions, so sending you this mail.

We want to enable and validate the following -
1. 2.5MHz channel bandwidth
2. 5.825GHz to 5.875GHz support

We are planning on using a Atheros device, which has not been validated
for the above two.

Question -
How do we enable these in the firmware, is it at the driver level in the
WLAN driver folder?

Appreciate your inputs.

Regards,
Sunil Mehta.

[ath9k-devel] Strange reception problem with ar9285

[Holger Schurig]

I can't really say. I'd have to dismount the device to find out ...
and presently I don't have the needed special screw driver for that at
hand.

AFAIK there's no tool that can give me reception statistics like it
used to exist for madwifi. Also

  grep ant /sys/kernel/debug/ieee80211/ath9k/*

doesn't show anything. So, any idea what I could try antenna-wise?

[ath9k-devel] Strange reception problem with ar9285

[Holger Schurig]

I peppered my code with debug statements. "##HS blah:123" means
function "blah()", line 123 in my source code
(compat-wireless-2012-05-08).

This log is from my office, where I didn't had a problem. Some
questions after the log:

ath9k 0000:01:00.0: PCI INT A -> GSI 16 (level, low) -> IRQ 16
ath9k 0000:01:00.0: setting latency timer to 64
##HS ath9k_set_hw_capab:723 rx 0x1, tx 0x1
##HS ath9k_set_hw_capab:729
ath: EEPROM regdomain: 0x60
ath: EEPROM indicates we should expect a direct regpair map
ath: Country alpha2 being used: 00
ath: Regpair used: 0x60
ieee80211 phy1: Selected rate control algorithm 'ath9k_rate_control'
Registered led device: ath9k-phy1
ieee80211 phy1: Atheros AR9285 Rev:2 mem=0xf8e60000, irq=16
ieee80211 phy1: device now idle
##HS ath9k_get_antenna:2392 rx 0x3, tx 0x1
##HS ath9k_get_antenna:2392 rx 0x3, tx 0x1
ieee80211 phy1: device no longer idle - scanning
##HS ath_rx_tasklet:1969 change def rx ant
##HS ath9k_hw_setantenna: 0x1
##HS ath_setdefantenna:113
ieee80211 phy1: device now idle
wlan0: authenticate with 00:a0:57:15:ba:0d
ieee80211 phy1: Allocated STA 00:a0:57:15:ba:0d
ieee80211 phy1: device no longer idle - in use
ieee80211 phy1: Inserted STA 00:a0:57:15:ba:0d
wlan0: send auth to 00:a0:57:15:ba:0d (try 1/3)
wlan0: authenticated
wlan0: moving STA 00:a0:57:15:ba:0d to state 2
wlan0: associate with 00:a0:57:15:ba:0d (try 1/3)
wlan0: RX AssocResp from 00:a0:57:15:ba:0d (capab=0x11 status=0 aid=1)
wlan0: associated
wlan0: moving STA 00:a0:57:15:ba:0d to state 3
wlan0: moving STA 00:a0:57:15:ba:0d to state 4

I don't know the hardware at all. What makes me wonder is this: in
ath9k_set_hw_capab() I print the contents of
hw->wiphy->available_antennas_rx and hw->wiphy->available_antennas_tx.
Both are one. So I assume I only have one antenna, or?

Later the code finds out that ATH9K_HW_CAP_ANT_DIV_COMB is set and
adds a second receive antenna. What is ATH9K_HW_CAP_ANT_DIV_COMB?
And, what would happen if my hardware only has one antenna, but this
capability if falsely set?

[ath9k-devel] Strange reception problem with ar9285

[Mohammed Shafi]

On Mon, May 14, 2012 at 1:07 PM, Holger Schurig
<holgerschurig@googlemail.com> wrote:
> I peppered my code with debug statements. "##HS blah:123" means
> function "blah()", line 123 in my source code
> (compat-wireless-2012-05-08).
>
> This log is from my office, where I didn't had a problem. Some
> questions after the log:
>
> ath9k 0000:01:00.0: PCI INT A -> GSI 16 (level, low) -> IRQ 16
> ath9k 0000:01:00.0: setting latency timer to 64
> ##HS ath9k_set_hw_capab:723 rx 0x1, tx 0x1
> ##HS ath9k_set_hw_capab:729
> ath: EEPROM regdomain: 0x60
> ath: EEPROM indicates we should expect a direct regpair map
> ath: Country alpha2 being used: 00
> ath: Regpair used: 0x60
> ieee80211 phy1: Selected rate control algorithm 'ath9k_rate_control'
> Registered led device: ath9k-phy1
> ieee80211 phy1: Atheros AR9285 Rev:2 mem=0xf8e60000, irq=16
> ieee80211 phy1: device now idle
> ##HS ath9k_get_antenna:2392 rx 0x3, tx 0x1
> ##HS ath9k_get_antenna:2392 rx 0x3, tx 0x1
> ieee80211 phy1: device no longer idle - scanning
> ##HS ath_rx_tasklet:1969 change def rx ant
> ##HS ath9k_hw_setantenna: 0x1
> ##HS ath_setdefantenna:113
> ieee80211 phy1: device now idle
> wlan0: authenticate with 00:a0:57:15:ba:0d
> ieee80211 phy1: Allocated STA 00:a0:57:15:ba:0d
> ieee80211 phy1: device no longer idle - in use
> ieee80211 phy1: Inserted STA 00:a0:57:15:ba:0d
> wlan0: send auth to 00:a0:57:15:ba:0d (try 1/3)
> wlan0: authenticated
> wlan0: moving STA 00:a0:57:15:ba:0d to state 2
> wlan0: associate with 00:a0:57:15:ba:0d (try 1/3)
> wlan0: RX AssocResp from 00:a0:57:15:ba:0d (capab=0x11 status=0 aid=1)
> wlan0: associated
> wlan0: moving STA 00:a0:57:15:ba:0d to state 3
> wlan0: moving STA 00:a0:57:15:ba:0d to state 4
>
> I don't know the hardware at all. What makes me wonder is this: in
> ath9k_set_hw_capab() I print the contents of
> hw->wiphy->available_antennas_rx and hw->wiphy->available_antennas_tx.
> Both are one. So I assume I only have one antenna, or?
>
> Later the code finds out that ATH9K_HW_CAP_ANT_DIV_COMB is set and
> adds a second receive antenna. What is ATH9K_HW_CAP_ANT_DIV_COMB?

antenna diverstiy, the rx antenna can be either in ant 0 or ant 1
based on which has better
recieving charactesristics

> And, what would happen if my hardware only has one antenna, but this
> capability if falsely set?
> _______________________________________________
> ath9k-devel mailing list
> ath9k-devel at lists.ath9k.org
> https://lists.ath9k.org/mailman/listinfo/ath9k-devel



-- 
thanks,
shafi

[ath9k-devel] Strange reception problem with ar9285

[Holger Schurig]

> antenna diverstiy, the rx antenna can be either in ant 0 or ant 1
> based on which has better recieving charactesristics

Okay, so it thinks it has two antenna inputs for receive diversity.
But if the PCI-express board physicall has only one connected... there
seems to be no way from userspace to tell it which to use?

(Actually I think my reception problem might be ANI related, I'm just
trying to understand the antenna stuff right now. If it would be an
antenna/diversity problem, then chances would be high that I get the
same problems everywhere, and not at just one location).