rt2870 USB adapter does not provide N speed.

[Archdevil]

Hi all!

I have this nice Eminent Em4556 usb wireless adapter.
My isp recently updated my connection to 40 Mbps.
Under linux, this adapter does not get faster than 26 Mbps.
Under windows (my kids play CoD) it reaches the 40 Mbps.
When I set my router to N-only, I cannot connect from linux.

So it looks like N does not work, although it should.

lsusb:

Bus 002 Device 006: ID 148f:2870 Ralink Technology, Corp.

Suggestions? Is this a common bug?
Any help would be appreciated.

Regards,

Archie.

[Archdevil]

I am still waiting for the first reaction! Is there noone with the same problem?

[AS]

Hello Archdevil,

do not have specific info about your adapter, however, as you probably know, wireless adapter use and adaptive technology to change the "on air" speed using some algorithm.

the only suggestions, right now are:
- check the real rate settings of your device using iwconfig, eventually you can force some fixed value, i.e. 54 Mb/s.
- check and report back what kernel are you using, eventually there could have been some improvements on recent kernels/rt2870 drivers
- you don't tell us how you measure the "speeds" you are reporting, are the wireless speed ? or the overall speed (wireless + ISP) ?

as of recent kernels (2.6.38.x) I do not see an rt2870 module available, only rt2870sta.

AS

[Archdevil]

Let me give you some information.

lsusb gives me:

Bus 002 Device 006: ID 148f:2870 Ralink Technology, Corp.

iwconfig:

wlan0     Ralink STA  ESSID:"Ziggo13E5C"  Nickname:"RT2870STA"
          Mode:Managed  Frequency=2.422 GHz  Access Point: 90:00:4E:78:A9:98
          Bit Rate=54 Mb/s
          RTS thr:off   Fragment thr:off
          Encryption key:031F-37E1-E4D2-1C94-4818-311C-53E6-1A49
          Link Quality=100/100  Signal level:-62 dBm  Noise level:-71 dBm
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:0   Missed beacon:0

lsmod | grep rt2*:

rt2800usb               9209  0
rt2800lib              20571  1 rt2800usb
rt2x00usb               8506  2 rt2800usb,rt2800lib
rt2x00lib              23616  2 rt2800lib,rt2x00usb
led_class               2692  1 rt2x00lib
mac80211              141920  2 rt2x00usb,rt2x00lib
cfg80211              102730  2 rt2x00lib,mac80211
crc_ccitt               1311  1 rt2800usb
rt2870sta             353826  1
iTCO_vendor_support     2302  1 iTCO_wdt
parport_pc             26665  0
rtc_cmos                6929  0
parport                28094  2 ppdev,parport_pc
usbcore               124336  15 snd_usb_audio,snd_usb_lib,rt2800usb,rt2x00usb,rt2870sta, btusb,uvcvideo,usblp,usb_storage,wacom,uhci_hcd,ohci_hcd,ehci_hcd,usbhid

Kernel:

2.6.33.7-pclos6.bfs

As iwconfig already shows, It gives me 54 mbps.
In practice, I get 26 mbps under linux and 40 mbps under windows.

stuff like "iwconfig wlan0 rate 300M fixed" does not do the trick.

I have seen more distros having the same problem in the past, but I do not know what the current situation is right now.


Regards,

Marcel.

[muungwana]

The latest kernel is "2.6.38.7", update to this kernel first and check to see if you the problem is still there.

Open synaptic, click "reload" then search for "kernel" and then install the kernel with that version, restart your computer and there will be the new kernel option on the boot up menu, boot up using this kernel and check if the problem is still there.

[Archdevil]

I have installed the kernel. Same result. iwconfig shows 54 mbps.

More suggestions?

[Archdevil]

Update:

I downloaded and ran the new Fedora live-cd on my system. The wireless problems do not appear with Fedora, so I suppose it is a configuration issue.
All suggestions are welcome. I have been playing with this issue for quite some time and I want it to be solved soon. I hope I can continue to use PCLinuxOS!