Unstable link with RaLink RT2500 802.11g Cardbus/mini-PCI

Live forum: http://rt2x00.serialmonkey.com/viewtopic.php?t=5213

raphy

21-02-2009 21:28:47

Hello,

I used the built-in rt2x00 driver from the 2.6.28 kernel, and they are several issue
-the link quality is low (i mean far lower that what it is with others drivers)
-every few minutes, the connections opened will hang for like 30 seconds, sometimes longer.
-default bitrate is 1 mbps
-bandwidth is low, about 30 ko/s (when it could be 15 times larger)
-new connection are very long to get established

Here is the /var/log/messages relevant (driver comiled with the debug option). During this "test", I tried to download the linux kernel while surfing on youtube.
[code31mae1c9]Feb 21 22:00:10 fitz cfg80211: Using static regulatory domain info
Feb 21 22:00:10 fitz cfg80211: Regulatory domain: US
Feb 21 22:00:10 fitz (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp)
Feb 21 22:00:10 fitz (2402000 KHz - 2472000 KHz @ 40000 KHz), (600 mBi, 2700 mBm)
Feb 21 22:00:10 fitz (5170000 KHz - 5190000 KHz @ 40000 KHz), (600 mBi, 2300 mBm)
Feb 21 22:00:10 fitz (5190000 KHz - 5210000 KHz @ 40000 KHz), (600 mBi, 2300 mBm)
Feb 21 22:00:10 fitz (5210000 KHz - 5230000 KHz @ 40000 KHz), (600 mBi, 2300 mBm)
Feb 21 22:00:10 fitz (5230000 KHz - 5330000 KHz @ 40000 KHz), (600 mBi, 2300 mBm)
Feb 21 22:00:10 fitz (5735000 KHz - 5835000 KHz @ 40000 KHz), (600 mBi, 3000 mBm)
Feb 21 22:00:10 fitz cfg80211: Calling CRDA for country: US
Feb 21 22:00:10 fitz rt2500pci 0000:01:0a.0: PCI INT A -> Link[APC3] -> GSI 18 (level, low) -> IRQ 18
Feb 21 22:00:10 fitz phy0 -> rt2500pci_validate_eeprom: EEPROM recovery - Calibrate offset: 0xff79
Feb 21 22:00:10 fitz phy0 -> rt2x00_set_chip: Info - Chipset detected - rt: 0201, rf: 0003, rev: 00000004.
Feb 21 22:00:10 fitz phy0: Selected rate control algorithm 'pid'
Feb 21 22:00:10 fitz Registered led device: rt2500pci-phy0:radio
Feb 21 22:00:10 fitz phy0 -> rt2x00mac_conf_tx: Info - Configured TX queue 0 - CWmin: 5, CWmax: 10, Aifs: 2, TXop: 0.
Feb 21 22:00:10 fitz phy0 -> rt2x00mac_conf_tx: Info - Configured TX queue 1 - CWmin: 5, CWmax: 10, Aifs: 2, TXop: 0.
Feb 21 22:00:10 fitz ADDRCONF(NETDEV_UP): wlan0: link is not ready
Feb 21 22:00:11 fitz phy0 -> rt2x00mac_conf_tx: Info - Configured TX queue 0 - CWmin: 4, CWmax: 10, Aifs: 2, TXop: 0.
Feb 21 22:00:11 fitz phy0 -> rt2x00mac_conf_tx: Info - Configured TX queue 1 - CWmin: 4, CWmax: 10, Aifs: 2, TXop: 0.
Feb 21 22:00:11 fitz wlan0: authenticate with AP 00:1e:37:12:4a:0f
Feb 21 22:00:11 fitz wlan0: authenticated
Feb 21 22:00:11 fitz wlan0: associate with AP 00:1e:37:12:4a:0f
Feb 21 22:00:11 fitz wlan0: RX AssocResp from 00:1e:37:12:4a:0f (capab=0x411 status=0 aid=2)
Feb 21 22:00:11 fitz wlan0: associated
Feb 21 22:00:11 fitz ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
Feb 21 22:00:21 fitz wlan0: no IPv6 routers present
Feb 21 22:05:36 fitz phy0 -> rt2x00mac_conf_tx: Info - Configured TX queue 0 - CWmin: 4, CWmax: 10, Aifs: 2, TXop: 0.
Feb 21 22:05:36 fitz phy0 -> rt2x00mac_conf_tx: Info - Configured TX queue 1 - CWmin: 4, CWmax: 10, Aifs: 2, TXop: 0.
Feb 21 22:05:36 fitz wlan0: direct probe to AP 00:1e:37:12:4a:0f try 1[/code31mae1c9]

Hope it helps

IvD

21-02-2009 22:45:27

Well the good news is that the driver partially works, I have bugreports from some Fedora users that the driver isn't associating at all. ;)


-the link quality is low (i mean far lower that what it is with others drivers)
[/quote2yfghajy]

The calculations for the quality is a bit differently, so that might explain the different values. Overall the "link quality" is a almost meaningless value of iwconfig since it is not defined what the value should represent. In the case of rt2x00 is combines the number of successfull transmitted frames, the number of successfull received frames and the link strength.


-every few minutes, the connections opened will hang for like 30 seconds, sometimes longer.
[/quote2yfghajy]

That is interesting, what is your estimation, is the maximum hang approximately 60 seconds?


-default bitrate is 1 mbps
-bandwidth is low, about 30 ko/s (when it could be 15 times larger)
[/quote2yfghajy]

These 2 issues are related, you have to force the bitrate to something higher, for example 'iwconfig wlan0 rate 54M'


-new connection are very long to get established
[/quote2yfghajy]

Is this also a problem after unloading and reloading the module? Or is this only when restarting the interface?

raphy

22-02-2009 10:29:18

The calculations for the quality is a bit differently, so that might explain the different values. Overall the "link quality" is a almost meaningless value of iwconfig since it is not defined what the value should represent. In the case of rt2x00 is combines the number of successfull transmitted frames, the number of successfull received frames and the link strength.[/quotezirlr894]

OK so I guess this is ok

That is interesting, what is your estimation, is the maximum hang approximately 60 seconds?

yeah, it is something like that.

These 2 issues are related, you have to force the bitrate to something higher, for example 'iwconfig wlan0 rate 54M'[/quotezirlr894]

unfortunately, forcing the bit rate to 54M doesn't change the maximum rate, which stays at about 30 ko/s. Even if iwconfig shows a bit rate of 54M.



Is this also a problem after unloading and reloading the module? Or is this only when restarting the interface?[/quotezirlr894][/quotezirlr894]

No, I mean that, one the link is open with the access point, new connections to remote server are long to established. Let's say I'm downloading the linux kernel, if meanwhile I want to go to http//www.google.com, the status bar of the browser will show "looking up for http//www.google.com" for like 30 seconds.

I'd say that the main problem is the speed.

raphy

25-02-2009 22:49:30

I tried the version in the kernel 2.6.29 rc6, and I have tosay that it is better (twice the speed, no deconnections,...). Keep up the good work!

kevinphilp

03-03-2009 16:39:27

I have a similar issue here on my Debian/Lenny box

I am getting about 70K/s download speed when it should be ~300

I have tweaked the rate up to 54M with iwconfig but it remains at about 1/5 the speed. If I boot and don't set the rate it defaults to 1M

I don't have a signal strength issue - the router is about 10' away

I am using WPA-PSK

Its frustrating because it works - just not fully...

My details are

0012.0 Network controller RaLink RT2500 802.11g Cardbus/mini-PCI (rev 01)
Subsystem RaLink Device 2560
Control I/O+ Mem+ BusMaster+ SpecCycle- MemWINV+ VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
Status Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=slow >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
Latency 32, Cache Line Size 32 bytes
Interrupt pin A routed to IRQ 10
Region 0 Memory at e6000000 (32-bit, non-prefetchable)
Capabilities [40] Power Management version 2
Flags PMEClk- DSI- D1- D2- AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-)
Status D0 PME-Enable- DSel=0 DScale=0 PME-
Kernel driver in use rt2500pci
Kernel modules rt2500pci


DMESG has some interesting items

[262307.128680] wlan0 authenticate with AP 000fcc258ce8
[262307.328058] wlan0 authenticate with AP 000fcc258ce8
[262307.528049] wlan0 authenticate with AP 000fcc258ce8
[262307.728050] wlan0 authentication with AP 000fcc258ce8 timed out
[262318.000841] wlan0 Initial auth_alg=0
[262318.000870] wlan0 authenticate with AP 000fcc258ce8
[262318.002877] wlan0 RX authentication from 000fcc258ce8 (alg=0 transaction=2 status=0)
[262318.002896] wlan0 authenticated
[262318.002912] wlan0 associate with AP 000fcc258ce8
[262318.006278] wlan0 RX ReassocResp from 000fcc258ce8 (capab=0x471 status=0 aid=1)
[262318.006338] wlan0 associated
[262318.006386] wlan0 switched to short barker preamble (BSSID=000fcc258ce8)

IvD

03-03-2009 16:46:26

Well raphy said 2.6.29 rcX is working better so you could try that.
I also added a fix to rt2x00.git, so that might help as well.

kevinphilp

05-03-2009 09:25:53

Problem solved - sort of...
I replaced the card last night. Both cards were Edimax 7128g cards but the first one was an older version based on the 2560F chip which uses the rt2500pci driver whereas the newer card, misleadingly also an Edimax 7128g is based on the 2561 chip and uses the rt61pci driver.

The newer card with the rt61 driver works perfect. I am getting the full 54M and my link quality reading is about 90%.

So my conclusion is that the problem was probably a driver issue with the rt2500pci driver and rt2560F chipset.

The good news is Edimax don't make the EW7128g with the 2560F chipset anymore!

Kevin.

ArCePi

17-04-2009 20:59:33

I'm also having an unstable link using rt2500pci driver in kernel 2.6.29.1. I have that card on a home server, and the unstabilities seem to begin when the computer has been running for 3 or 4 days without rebooting. At the same time that the unstabilities begin, latency to that machine raises from around 2-3 ms to 15-25 ms and packet loss raises from 1% to ~40%.

That latency issue has nothing to do with "air" conditions, such as interference, because if I connect my laptop (using the ath9k driver) to the same ESSID and AP, it gets the usual 2ms latency and a stable, fast network connectivity.

I have also a slow transfer rate, of around 70 kB/s download and upload. But the most annoying part is having that packet loss and high latency.

Maybe the information that the problems begin when the machine has some days of uptime is useful.

Can I provide any more information?