2.6 much worse than 2.4 on poor wlan reception

2.6 much worse than 2.4 on poor wlan reception

[Thomas Mueller]

Hi,

I have big problems with kernel 2.6 and WLAN. Quite often the connection
interrupts completely, I can't transfer anything for minutes - making
2.6 unusable for me :-(
I'm only about 5 meters away from my AP, but unfortunately there's a
celeiling between me and the AP to the reception is poor.

My hardware is a SMC 2632 PCMCIA card (802.11b) in a IBM Thinkpad A30
and a SMC AP.

lspci:
02:00.0 CardBus bridge: Ricoh Co Ltd RL5c476 II (rev 80)
02:00.1 CardBus bridge: Ricoh Co Ltd RL5c476 II (rev 80)

blade:~# cardctl ident
Socket 0:
  no product info available
Socket 1:
  product info: "SMC", "SMC2632W", "Version 01.02", ""
  manfid: 0x0156, 0x0002
  function: 6 (network)

The wireless-tools have version 26+27pre10-3, pcmcia-cs has 3.2.5, both
from Debian Sid. I have tried kernels 2.6.0, .1 and .2.
Every kernel 2.4 I've had running until now worked very well.

-----------------------------------------------------------
2.4.20:

blade:~# iwconfig eth1
eth1      IEEE 802.11-DS  ESSID:"WLAN"  Nickname:"Prism  I"
          Mode:Managed  Frequency:2.412GHz  Access Point:00:60:B3:17:F8:8C
          Bit Rate:11Mb/s   Tx-Power=15 dBm   Sensitivity:1/3
          Retry min limit:8   RTS thr:off   Fragment thr:off
          Encryption key:[ secret ]   Security mode:open
          Power Management:off
          Link Quality:1/92  Signal level:-101 dBm  Noise level:-149 dBm
          Rx invalid nwid:0  Rx invalid crypt:661  Rx invalid frag:0
          Tx excessive retries:2751  Invalid misc:0   Missed beacon:0

lsmod:
orinoco_cs              4776   1
orinoco                32068   0  [orinoco_cs]
hermes                  6244   0  [orinoco_cs orinoco]
ds                      7060   2  [orinoco_cs]
yenta_socket           10080   2
pcmcia_core            44928   0  [orinoco_cs ds yenta_socket]

tmm@blade:~$ netio -u 10.0.0.15
 NETIO - Network Throughput Benchmark, Version 1.21
(C) 1997-2003 Kai Uwe Rommel
 
UDP connection established.
Packet size  1k bytes:  557 KByte/s (0%) Tx,  261 KByte/s (73%) Rx.
Packet size  2k bytes:  553 KByte/s (0%) Tx,  89 KByte/s (90%) Rx.
Packet size  4k bytes:  626 KByte/s (0%) Tx,  61444 Byte/s (92%) Rx.
Packet size  8k bytes:  517 KByte/s (2%) Tx,  13393 Byte/s (98%) Rx.
Packet size 16k bytes:  565 KByte/s (3%) Tx,  10924 Byte/s (98%) Rx.
Packet size 32k bytes:  565 KByte/s (3%) Tx,  13787 Byte/s (98%) Rx.
Done.

-----------------------------------------------------------
2.6.2:

blade:~# iwconfig eth1
eth1      IEEE 802.11-DS  ESSID:"WLAN"  Nickname:"Prism  I"
          Mode:Managed  Frequency:2.412GHz  Access Point:00:60:B3:17:F8:8C
          Bit Rate:11Mb/s   Tx-Power=15 dBm   Sensitivity:1/3
          Retry min limit:8   RTS thr:off   Fragment thr:off
          Encryption key:[ secret ]   Security mode:open
          Power Management:off
          Link Quality:1/92  Signal level:-101 dBm  Noise level:-149 dBm
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:0   Missed beacon:0

orinoco_cs              9192  1
orinoco                43980  1 orinoco_cs
hermes                  8512  2 orinoco_cs,orinoco
ds                     15940  5 orinoco_cs
i82365                 20876  1
pcmcia_core            71456  3 orinoco_cs,ds,i82365

tmm@blade:~$ netio -u 10.0.0.15
 
NETIO - Network Throughput Benchmark, Version 1.21
(C) 1997-2003 Kai Uwe Rommel
 
UDP connection established.
Packet size  1k bytes:  289 KByte/s (99%) Tx,  223 KByte/s (75%) Rx.
Packet size  2k bytes:  0 Byte/s (100%) Tx,  21 KByte/s (91%) Rx.
Packet size  4k bytes:  440 KByte/s (99%) Tx,  61333 Byte/s (94%) Rx.
Packet size  8k bytes:  382 KByte/s (96%) Tx,  14438 Byte/s (98%) Rx.
Packet size 16k bytes:  369 KByte/s (96%) Tx,  2365 Byte/s (98%) Rx.
Packet size 32k bytes:  239 KByte/s (98%) Tx,  3005 Byte/s (98%) Rx.
Done.

There was a break when netio transfered the 2k blocks.

My log is full of entries like this one:
Mar  1 17:54:12 blade kernel: eth1: New link status: AP Out of Range
(0004)
Mar  1 17:54:12 blade kernel: eth1: New link status: AP In Range (0005)
Mar  1 17:54:16 blade kernel: eth1: New link status: AP Out of Range
(0004)
Mar  1 17:54:16 blade kernel: eth1: New link status: AP In Range (0005)
Mar  1 17:54:19 blade kernel: eth1: New link status: AP Out of Range
(0004)
Mar  1 17:54:20 blade kernel: eth1: New link status: AP In Range (0005)
Mar  1 17:54:22 blade kernel: eth1: New link status: AP Out of Range
(0004)

Kernel 2.4 works far better in the poor reception situation I have,
anyone any idea what I could do without moving the AP or laptop?
When I'm near my AP everything works fine with 2.6 too.

BTW: removing the PCMCIA card when it's in use freezes my system
completely, that was no problem with 2.4.

Thanks a lot!


-- 
Thomas Mueller - http://www.tmueller.com for pgp key (95702B3B)

Re: 2.6 much worse than 2.4 on poor wlan reception

[Denis Vlasenko]

On Thursday 04 March 2004 20:01, Thomas Mueller wrote:
> I have big problems with kernel 2.6 and WLAN. Quite often the connection
> interrupts completely, I can't transfer anything for minutes - making
> 2.6 unusable for me :-(

> blade:~# iwconfig eth1
> eth1      IEEE 802.11-DS  ESSID:"WLAN"  Nickname:"Prism  I"
>           Mode:Managed  Frequency:2.412GHz  Access Point:00:60:B3:17:F8:8C
>           Bit Rate:11Mb/s   Tx-Power=15 dBm   Sensitivity:1/3
>           Retry min limit:8   RTS thr:off   Fragment thr:off
>           Encryption key:[ secret ]   Security mode:open
>           Power Management:off
>           Link Quality:1/92  Signal level:-101 dBm  Noise level:-149 dBm

I have Prism 2.5 cards. I run them with hostap driver.
Link quality of 1/92 is very bad. You are on the edge
of losing connection. (At least this is the case for
my hardware).

Let's see how much errors do you have. Do this:

# cat /proc/net/wireless /proc/net/dev

On my system wlan1 has "Link Quality:66/92"
(wlan0 is an AP, has no meaningful Link Quality)

Inter-| sta-|   Quality        |   Discarded packets               | Missed | WE
 face | tus | link level noise |  nwid  crypt   frag  retry   misc | beacon | 16
 wlan0: 0000    0     0     0        0   9178     13  23727 142280        0
 wlan1: 0000   66.  195.  156.       0      0      0   3422 309008        0

Inter-|   Receive                                                |  Transmit
 face |bytes    packets errs drop fifo frame compressed multicast|bytes    packets errs drop fifo colls carrier compressed
 wlan0:1829928225 2539552    0 80689    0     0          0         0 1966341385 2579089    0   42    0     0       0          0
 wlan1:143242367  907236    0    0    0     0          0         0 11481487   74357    0    0    0     0       0          0

So, wlan1: 907236 rx packets, 3422 retries
(and 309008 packets wasn't for me, wrong MAC, I suppose ;) )
What's your numbers?

> There was a break when netio transfered the 2k blocks.
>
> My log is full of entries like this one:
> Mar  1 17:54:12 blade kernel: eth1: New link status: AP Out of Range
> (0004)
> Mar  1 17:54:12 blade kernel: eth1: New link status: AP In Range (0005)
> Mar  1 17:54:16 blade kernel: eth1: New link status: AP Out of Range
> (0004)
> Mar  1 17:54:16 blade kernel: eth1: New link status: AP In Range (0005)
> Mar  1 17:54:19 blade kernel: eth1: New link status: AP Out of Range
> (0004)
> Mar  1 17:54:20 blade kernel: eth1: New link status: AP In Range (0005)
> Mar  1 17:54:22 blade kernel: eth1: New link status: AP Out of Range
> (0004)
>
> Kernel 2.4 works far better in the poor reception situation I have,
> anyone any idea what I could do without moving the AP or laptop?
> When I'm near my AP everything works fine with 2.6 too.

Is your orinoco driver is the same for 2.4 and 2.6?
Maybe 2.6 one has a bit lower max retry count or some such?

> BTW: removing the PCMCIA card when it's in use freezes my system
> completely, that was no problem with 2.4.

No oops? No SysRq?
--
vda

Re: 2.6 much worse than 2.4 on poor wlan reception

[Jes Sorensen]

>>>>> "Thomas" == Thomas Mueller <linux-kernel@tmueller.com> writes:

Thomas> Kernel 2.4 works far better in the poor reception situation I
Thomas> have, anyone any idea what I could do without moving the AP or
Thomas> laptop?  When I'm near my AP everything works fine with 2.6
Thomas> too.

Start out by forcing it to a lower link speed, at that signal quality
you really don't want to try and go above 2MBit/sec. If you keep
trying to do 11MBit/sec the card will constantly try the higher rate
and then lose signal, drop down and try again. Fixing the rate should
improve the situation - at least it has always done so for me ;-)

Cheers,
Jes

Re: 2.6 much worse than 2.4 on poor wlan reception

[Thomas Mueller]

Hi Jes,

Jes Sorensen meinte am Friday, dem 05. March 2004:

> Thomas> Kernel 2.4 works far better in the poor reception situation I
> Thomas> have, anyone any idea what I could do without moving the AP or
> Thomas> laptop?  When I'm near my AP everything works fine with 2.6
> Thomas> too.
> 
> Start out by forcing it to a lower link speed, at that signal quality
> you really don't want to try and go above 2MBit/sec. If you keep
> trying to do 11MBit/sec the card will constantly try the higher rate
> and then lose signal, drop down and try again. Fixing the rate should
> improve the situation - at least it has always done so for me ;-)

I tried that (rate 2M auto) but that doesn't improve anything. I still
loose the connection to the AP, I don't think that happens less frequent
than at 11 MBit/s.


-- 
MfG Thomas Mueller - http://www.tmueller.com for pgp key (95702B3B)

Re: 2.6 much worse than 2.4 on poor wlan reception

[Thomas Mueller]

Hi Denis,

> > blade:~# iwconfig eth1
> > eth1      IEEE 802.11-DS  ESSID:"WLAN"  Nickname:"Prism  I"
> >           Mode:Managed  Frequency:2.412GHz  Access Point:00:60:B3:17:F8:8C
> >           Bit Rate:11Mb/s   Tx-Power=15 dBm   Sensitivity:1/3
> >           Retry min limit:8   RTS thr:off   Fragment thr:off
> >           Encryption key:[ secret ]   Security mode:open
> >           Power Management:off
> >           Link Quality:1/92  Signal level:-101 dBm  Noise level:-149 dBm
> 
> I have Prism 2.5 cards. I run them with hostap driver.
> Link quality of 1/92 is very bad. You are on the edge
> of losing connection. (At least this is the case for
> my hardware).

Yes I am. When I move some meters in the room I loose connection with
kernel 2.4 too.

> Let's see how much errors do you have. Do this:
> 
> # cat /proc/net/wireless /proc/net/dev
[..]

tmm@blade:~$ cat /proc/net/wireless /proc/net/dev
Inter-| sta-|   Quality        |   Discarded packets               |
Missed | WE
 face | tus | link level noise |  nwid  crypt   frag  retry   misc |
beacon | 16
  eth1: 0000    0.  150.  107.       0      8      0      0      0
0
Inter-|   Receive                                                |
Transmit
 face |bytes    packets errs drop fifo frame compressed multicast|bytes
packets errs drop fifo colls carrier compressed
    lo:   58298     881    0    0    0     0          0         0
58298     881    0    0    0     0       0          0
  eth0:       0       0    0    0    0     0          0         0
3456      14    0    0    0     0       0          0
  eth1:  532101    1336    0    0    0     0          0         0
223614    1299  466    0    0     0       0          0
  sit0:       0       0    0    0    0     0          0         0
0       0    0    0    0     0       0          0

That's really interesting, thanks for that hint!
Transmit: 1299 packets, 466 errs - argh.

When I can't transmit anything 'errs' increases by one every few
seconds.

As comparison: kernel 2.4.20 has 1743 packets and 9 errs at the moment.
So the interesting question is: why is the error rate with kernel 2.6
that high?

> > There was a break when netio transfered the 2k blocks.
> >
> > My log is full of entries like this one:
> > Mar  1 17:54:12 blade kernel: eth1: New link status: AP Out of Range
> > (0004)
> > Mar  1 17:54:12 blade kernel: eth1: New link status: AP In Range (0005)
> > Mar  1 17:54:16 blade kernel: eth1: New link status: AP Out of Range
> > (0004)
> > Mar  1 17:54:16 blade kernel: eth1: New link status: AP In Range (0005)
> > Mar  1 17:54:19 blade kernel: eth1: New link status: AP Out of Range
> > (0004)
> > Mar  1 17:54:20 blade kernel: eth1: New link status: AP In Range (0005)
> > Mar  1 17:54:22 blade kernel: eth1: New link status: AP Out of Range
> > (0004)
> >
> > Kernel 2.4 works far better in the poor reception situation I have,
> > anyone any idea what I could do without moving the AP or laptop?
> > When I'm near my AP everything works fine with 2.6 too.
> 
> Is your orinoco driver is the same for 2.4 and 2.6?
> Maybe 2.6 one has a bit lower max retry count or some such?

2.6.2 has version 0.13e, 2.4.23 has 0.13d. I diffed the orinoco.* but
there are only small changes.

> > BTW: removing the PCMCIA card when it's in use freezes my system
> > completely, that was no problem with 2.4.
> 
> No oops? No SysRq?

Nope, it just freezes :-(


-- 
MfG Thomas Mueller - http://www.tmueller.com for pgp key (95702B3B)