Re: Need help with porting iwn driver

To: David Young <dyoung%pobox.com@localhost>
Subject: Re: Need help with porting iwn driver
From: Sverre Froyen <sverre%viewmark.com@localhost>
Date: Mon, 12 Apr 2010 20:42:10 -0600
On Tue March 30 2010 16:01:09 David Young wrote:
> On Tue, Mar 30, 2010 at 09:43:36AM -0600, Sverre Froyen wrote:
> > Hi,
> > 
> > I've been attempting to port the latest iwn driver from OpenBSD.  I have
> > been able to get it running but I'm having a couple of issues that I was
> > hoping somebody might have some insight into.
> 
> Is there any reason that you port from OpenBSD instead of from FreeBSD?
> 
> > The hardware is an Intel 5100 adapter connecting to a Linksys 11g
> > access point. I'm using WAP2. This is on amd64/current.
> > 
> > Immediately after boot and most of the time with only "normal" network
> > activity, the adapter works fine.
> > 
> > When I use it with a network TV tuner (HDHomeRun from Silicondust),
> > however, the interface will sometimes get locked into what appears
> > to be a slow-speed mode. When this happens, I can usually get the
> > interface working again by doing "ifconfig iwn0 down/up". The TV tuner
> > sends the video signal as a stream of UDP packets. When the interface
> > is working correctly, I see around 1500 packets per second. When
> > it is stuck, this drops to just over 75 packets per second. Since
> > each packet is around 1400 bytes, the stuck mode might be DS1 (1
> > Mb/s). I've noticed that "ifconfig iwn0" sometimes reports DS1 when
> > this happens -- but not always.
> 
> It sounds to me like the AP sends the packets.  The AP and your NetBSD
> box select the transmission rate independently of each other.
> 
> What rates do the AP and your NetBSD box negotiate? 'wlanctl iwn0' will
> tell us.
> 
> You can find out the rate that the AP transmits at with 'tcpdump -nel -y
> ieee802_11_radio -i iwn0'.
> 
> > The frequency of the interface getting stuck may depend on the wireness
> > activity in the neighborhood. I have also noticed that the channel
> > setting on the access point affects the speed.
> 
> Oftentimes tcpdump can show us the activity that is not on the same
> network (i.e., same BSSID) but that is on the same channel.  That might
> be worth a look.

Here are results from the three commands when the interface if working 
properly:

# ifconfig iwn0
iwn0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        ssid fesk nwkey *****
        powersave off
        bssid 00:12:17:60:ba:43 chan 10
        address: 00:16:ea:bb:89:c8
        media: IEEE802.11 autoselect (OFDM18 mode 11g)
        status: active
        inet 192.168.2.5 netmask 0xffffff00 broadcast 192.168.2.255
        inet6 fe80::216:eaff:febb:89c8%iwn0 prefixlen 64 scopeid 0x2
# wlanctl iwn0
iwn0: mac 00:12:17:60:ba:43 bss 00:12:17:60:ba:43
        node flags 0005<bss,scan>
        ess <fesk>
        chan 10 freq 2457MHz flags 04e0<cck,ofdm,2.4GHz,dynamic cck-ofdm>
        capabilities 0411<ess,privacy,short slot-time>
        beacon-interval 100 TU tsft 136782234380 us
        rates 1.0 2.0 5.5 6.0 9.0 11.0 12.0 [18.0] 24.0 36.0 48.0 54.0
        assoc-id 49154 assoc-failed 0 inactivity 300s
        rssi 215 txseq 26394 rxseq 42320
# tcpdump -nel -c 20 -y ieee802_11_radio -i iwn0
13:53:10.994504 136782253228us tsft 54.0 Mb/s 2457 MHz (0x04e0) -41dB signal 
-87dB noise DA:00:16:ea:bb:89:c8 BSSID:00:12:17:60:ba:43 SA:00:18:dd:01:7b:2f 
Data IV:4c6b Pad 20 KeyID 0
13:53:10.995231 136782253955us tsft 54.0 Mb/s 2457 MHz (0x04e0) -41dB signal 
-87dB noise DA:00:16:ea:bb:89:c8 BSSID:00:12:17:60:ba:43 SA:00:18:dd:01:7b:2f 
Data IV:4c6c Pad 20 KeyID 0
13:53:11.005090 136782263815us tsft 54.0 Mb/s 2457 MHz (0x04e0) -41dB signal 
-87dB noise DA:00:16:ea:bb:89:c8 BSSID:00:12:17:60:ba:43 SA:00:18:dd:01:7b:2f 
Data IV:4c6d Pad 20 KeyID 0
13:53:11.006150 136782264875us tsft 54.0 Mb/s 2457 MHz (0x04e0) -41dB signal 
-87dB noise DA:00:16:ea:bb:89:c8 BSSID:00:12:17:60:ba:43 SA:00:18:dd:01:7b:2f 
Data IV:4c6e Pad 20 KeyID 0
13:53:11.006570 136782265295us tsft 54.0 Mb/s 2457 MHz (0x04e0) -41dB signal 
-87dB noise DA:00:16:ea:bb:89:c8 BSSID:00:12:17:60:ba:43 SA:00:18:dd:01:7b:2f 
Data IV:4c6f Pad 20 KeyID 0
13:53:11.007458 136782266181us tsft 54.0 Mb/s 2457 MHz (0x04e0) -41dB signal 
-87dB noise DA:00:16:ea:bb:89:c8 BSSID:00:12:17:60:ba:43 SA:00:18:dd:01:7b:2f 
Data IV:4c70 Pad 20 KeyID 0
13:53:11.008181 136782266906us tsft 54.0 Mb/s 2457 MHz (0x04e0) -41dB signal 
-87dB noise DA:00:16:ea:bb:89:c8 BSSID:00:12:17:60:ba:43 SA:00:18:dd:01:7b:2f 
Data IV:4c71 Pad 20 KeyID 0
13:53:11.008475 136782267201us tsft 54.0 Mb/s 2457 MHz (0x04e0) -41dB signal 
-87dB noise DA:00:16:ea:bb:89:c8 BSSID:00:12:17:60:ba:43 SA:00:18:dd:01:7b:2f 
Data IV:4c72 Pad 20 KeyID 0
13:53:11.008770 136782267495us tsft 54.0 Mb/s 2457 MHz (0x04e0) -41dB signal 
-87dB noise DA:00:16:ea:bb:89:c8 BSSID:00:12:17:60:ba:43 SA:00:18:dd:01:7b:2f 
Data IV:4c73 Pad 20 KeyID 0
13:53:11.009067 136782267789us tsft 54.0 Mb/s 2457 MHz (0x04e0) -41dB signal 
-87dB noise DA:00:16:ea:bb:89:c8 BSSID:00:12:17:60:ba:43 SA:00:18:dd:01:7b:2f 
Data IV:4c74 Pad 20 KeyID 0
13:53:11.009359 136782268084us tsft 54.0 Mb/s 2457 MHz (0x04e0) -41dB signal 
-87dB noise DA:00:16:ea:bb:89:c8 BSSID:00:12:17:60:ba:43 SA:00:18:dd:01:7b:2f 
Data IV:4c75 Pad 20 KeyID 0
13:53:11.009906 136782268629us tsft 54.0 Mb/s 2457 MHz (0x04e0) -41dB signal 
-87dB noise DA:00:16:ea:bb:89:c8 BSSID:00:12:17:60:ba:43 SA:00:18:dd:01:7b:2f 
Data IV:4c76 Pad 20 KeyID 0
13:53:11.010199 136782268924us tsft 54.0 Mb/s 2457 MHz (0x04e0) -41dB signal 
-87dB noise DA:00:16:ea:bb:89:c8 BSSID:00:12:17:60:ba:43 SA:00:18:dd:01:7b:2f 
Data IV:4c77 Pad 20 KeyID 0
13:53:11.010496 136782269218us tsft 54.0 Mb/s 2457 MHz (0x04e0) -41dB signal 
-87dB noise DA:00:16:ea:bb:89:c8 BSSID:00:12:17:60:ba:43 SA:00:18:dd:01:7b:2f 
Data IV:4c78 Pad 20 KeyID 0
13:53:11.010923 136782269648us tsft 54.0 Mb/s 2457 MHz (0x04e0) -41dB signal 
-87dB noise DA:00:16:ea:bb:89:c8 BSSID:00:12:17:60:ba:43 SA:00:18:dd:01:7b:2f 
Data IV:4c79 Pad 20 KeyID 0
13:53:11.011217 136782269942us tsft 54.0 Mb/s 2457 MHz (0x04e0) -41dB signal 
-87dB noise DA:00:16:ea:bb:89:c8 BSSID:00:12:17:60:ba:43 SA:00:18:dd:01:7b:2f 
Data IV:4c7a Pad 20 KeyID 0
13:53:11.011513 136782270237us tsft 54.0 Mb/s 2457 MHz (0x04e0) -41dB signal 
-87dB noise DA:00:16:ea:bb:89:c8 BSSID:00:12:17:60:ba:43 SA:00:18:dd:01:7b:2f 
Data IV:4c7b Pad 20 KeyID 0
13:53:11.011890 136782270612us tsft 54.0 Mb/s 2457 MHz (0x04e0) -41dB signal 
-87dB noise DA:00:16:ea:bb:89:c8 BSSID:00:12:17:60:ba:43 SA:00:18:dd:01:7b:2f 
Data IV:4c7c Pad 20 KeyID 0
13:53:11.012183 136782270907us tsft 54.0 Mb/s 2457 MHz (0x04e0) -41dB signal 
-87dB noise DA:00:16:ea:bb:89:c8 BSSID:00:12:17:60:ba:43 SA:00:18:dd:01:7b:2f 
Data IV:4c7d Pad 20 KeyID 0
13:53:11.012478 136782271202us tsft 54.0 Mb/s 2457 MHz (0x04e0) -41dB signal 
-87dB noise DA:00:16:ea:bb:89:c8 BSSID:00:12:17:60:ba:43 SA:00:18:dd:01:7b:2f 
Data IV:4c7e Pad 20 KeyID 0

and here are the results when it is stuck in "slow" mode.

# ifconfig iwn0
iwn0: flags=8943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1500
        ssid fesk nwkey *****
        powersave off
        bssid 00:12:17:60:ba:43 chan 10
        address: 00:16:ea:bb:89:c8
        media: IEEE802.11 autoselect (DS1 mode 11g)
        status: active
        inet 192.168.2.5 netmask 0xffffff00 broadcast 192.168.2.255
        inet6 fe80::216:eaff:febb:89c8%iwn0 prefixlen 64 scopeid 0x2
# wlanctl iwn0
iwn0: mac 00:12:17:60:ba:43 bss 00:12:17:60:ba:43
        node flags 0005<bss,scan>
        ess <fesk>
        chan 10 freq 2457MHz flags 04e0<cck,ofdm,2.4GHz,dynamic cck-ofdm>
        capabilities 0411<ess,privacy,short slot-time>
        beacon-interval 100 TU tsft 154313728782 us
        rates [1.0] 2.0 5.5 6.0 9.0 11.0 12.0 18.0 24.0 36.0 48.0 54.0
        assoc-id 49154 assoc-failed 0 inactivity 300s
        rssi 212 txseq 3244 rxseq 52080
# tcpdump -nel -c 20 -y ieee802_11_radio -i iwn0
18:45:22.603187 154313916853us tsft 1.0 Mb/s 2457 MHz (0x04e0) -44dB signal 
-77dB noise DA:00:16:ea:bb:89:c8 BSSID:00:12:17:60:ba:43 SA:00:18:dd:01:7b:2f 
Data IV:99ed Pad 20 KeyID 0
18:45:22.614992 154313928661us tsft 1.0 Mb/s 2457 MHz (0x04e0) -45dB signal 
-77dB noise DA:00:16:ea:bb:89:c8 BSSID:00:12:17:60:ba:43 SA:00:18:dd:01:7b:2f 
Data IV:99ee Pad 20 KeyID 0
18:45:22.630507 154313944175us tsft 1.0 Mb/s 2457 MHz (0x04e0) -45dB signal 
-77dB noise DA:00:16:ea:bb:89:c8 BSSID:00:12:17:60:ba:43 SA:00:18:dd:01:7b:2f 
Data IV:99ee Pad 20 KeyID 0
18:45:22.670821 154313984490us tsft 1.0 Mb/s 2457 MHz (0x04e0) -44dB signal 
-77dB noise DA:00:16:ea:bb:89:c8 BSSID:00:12:17:60:ba:43 SA:00:18:dd:01:7b:2f 
Data IV:99ee Pad 20 KeyID 0
18:45:22.682718 154313996388us tsft 1.0 Mb/s 2457 MHz (0x04e0) -43dB signal 
-77dB noise DA:00:16:ea:bb:89:c8 BSSID:00:12:17:60:ba:43 SA:00:18:dd:01:7b:2f 
Data IV:99ef Pad 20 KeyID 0
18:45:22.720347 154314034015us tsft 1.0 Mb/s 2457 MHz (0x04e0) -45dB signal 
-77dB noise DA:00:16:ea:bb:89:c8 BSSID:00:12:17:60:ba:43 SA:00:18:dd:01:7b:2f 
Data IV:99ef Pad 20 KeyID 0
18:45:22.721513 154314045904us tsft 1.0 Mb/s 2457 MHz (0x04e0) -44dB signal 
-77dB noise BSSID:00:12:17:60:ba:43 DA:ff:ff:ff:ff:ff:ff SA:00:12:17:60:ba:43 
Beacon[|802.11]
18:45:22.733401 154314047072us tsft 1.0 Mb/s 2457 MHz (0x04e0) -43dB signal 
-87dB noise DA:00:16:ea:bb:89:c8 BSSID:00:12:17:60:ba:43 SA:00:18:dd:01:7b:2f 
Data IV:99f0 Pad 20 KeyID 0
18:45:22.770667 154314084335us tsft 1.0 Mb/s 2457 MHz (0x04e0) -45dB signal 
-87dB noise DA:00:16:ea:bb:89:c8 BSSID:00:12:17:60:ba:43 SA:00:18:dd:01:7b:2f 
Data IV:99f0 Pad 20 KeyID 0
18:45:22.782597 154314096269us tsft 1.0 Mb/s 2457 MHz (0x04e0) -44dB signal 
-87dB noise DA:00:16:ea:bb:89:c8 BSSID:00:12:17:60:ba:43 SA:00:18:dd:01:7b:2f 
Data IV:99f1 Pad 20 KeyID 0
18:45:22.914118 154314227788us tsft 1.0 Mb/s 2457 MHz (0x04e0) -45dB signal 
-87dB noise DA:00:16:ea:bb:89:c8 BSSID:00:12:17:60:ba:43 SA:00:18:dd:01:7b:2f 
Data IV:99f2 Pad 20 KeyID 0
18:45:22.930183 154314243854us tsft 1.0 Mb/s 2457 MHz (0x04e0) -44dB signal 
-87dB noise DA:00:16:ea:bb:89:c8 BSSID:00:12:17:60:ba:43 SA:00:18:dd:01:7b:2f 
Data IV:99f2 Pad 20 KeyID 0
18:45:22.945893 154314259562us tsft 1.0 Mb/s 2457 MHz (0x04e0) -42dB signal 
-87dB noise DA:00:16:ea:bb:89:c8 BSSID:00:12:17:60:ba:43 SA:00:18:dd:01:7b:2f 
Data IV:99f2 Pad 20 KeyID 0
18:45:22.982936 154314296606us tsft 1.0 Mb/s 2457 MHz (0x04e0) -45dB signal 
-87dB noise DA:00:16:ea:bb:89:c8 BSSID:00:12:17:60:ba:43 SA:00:18:dd:01:7b:2f 
Data IV:99f3 Pad 20 KeyID 0
18:45:23.000499 154314314169us tsft 1.0 Mb/s 2457 MHz (0x04e0) -45dB signal 
-87dB noise DA:00:16:ea:bb:89:c8 BSSID:00:12:17:60:ba:43 SA:00:18:dd:01:7b:2f 
Data IV:99f3 Pad 20 KeyID 0
18:45:23.025844 154314350234us tsft 1.0 Mb/s 2457 MHz (0x04e0) -45dB signal 
-87dB noise BSSID:00:12:17:60:ba:43 DA:ff:ff:ff:ff:ff:ff SA:00:12:17:60:ba:43 
Beacon[|802.11]
18:45:23.087033 154314400702us tsft 1.0 Mb/s 2457 MHz (0x04e0) -43dB signal 
-87dB noise DA:00:16:ea:bb:89:c8 BSSID:00:12:17:60:ba:43 SA:00:18:dd:01:7b:2f 
Data IV:99f4 Pad 20 KeyID 0
18:45:23.125389 154314449782us tsft 1.0 Mb/s 2457 MHz (0x04e0) -43dB signal 
-87dB noise BSSID:00:12:17:60:ba:43 DA:ff:ff:ff:ff:ff:ff SA:00:12:17:60:ba:43 
Beacon[|802.11]
18:45:23.436860 154314750530us tsft 1.0 Mb/s 2457 MHz (0x04e0) -42dB signal 
-89dB noise DA:00:16:ea:bb:89:c8 BSSID:00:12:17:60:ba:43 SA:00:18:dd:01:7b:2f 
Data IV:99f8 Pad 20 KeyID 0
18:45:23.438028 154314762419us tsft 1.0 Mb/s 2457 MHz (0x04e0) -42dB signal 
-89dB noise BSSID:00:12:17:60:ba:43 DA:ff:ff:ff:ff:ff:ff SA:00:12:17:60:ba:43 
Beacon[|802.11]

I don't see anything obvious differences except for the much lower speed in the 
second trace. ifconfig iwn0 shows the interface in promiscuous mode. that is 
because I was running a second tcpdump command searching for packets from 
another BSSID. There were none. (The second tcpdump had been running for a 
*long* time before the interface slowed and is therefore not likely to be part 
of the problem.)

Any ideas?

Thanks,
Sverre

PS The hard lockup problem that I decribed in my initial email has been 
resolved. See the thread beginning with http://mail-index.netbsd.org/tech-
net/2010/04/05/msg002001.html
References:
- Need help with porting iwn driver
  - From: Sverre Froyen
- Re: Need help with porting iwn driver
  - From: David Young
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