Red Hat Bugzilla – Bug 382781
wifi regression in rt2500pci module with 18.104.22.168-49.fc8
Last modified: 2008-01-14 09:10:02 EST
From Bugzilla Helper:
User-Agent: Mozilla/5.0 (X11; U; Linux i686; fr; rv:22.214.171.124) Gecko/20071030 Fedora/126.96.36.199-2.fc8 Firefox/188.8.131.52
Description of problem:
Booting the 184.108.40.206-49.fc8 kernel with wlan0 enable at boot leads to erratic transfer rate. Booting 220.127.116.11-42.fc8 in the same condition leads to a stable transfer rate.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1.Boot kernel 18.104.22.168-49.fc8
2.test transfer rate with another machine in the same lan
3.see an erratic instant transfer rate
Might I ask you to try a few earlier .fc8 kernels, to see if any of them are
more stable w.r.t. wireless?
Which kernels work better?
Now i work with kernel 22.214.171.124-42.fc8 and the connection is very stable so the
regression seems to be between 126.96.36.199-42.fc8 and 188.8.131.52-49.fc8. Which kernel
do you want i try ?
It is a longshot, but please try these kernels:
Do you get stable throughput with these kernels?
I tried kernel-184.108.40.206-53.wl.1.fc8.i686 and the problem is still here. Do not
hesitate to ask me more test.
These have more extensive wireless updates:
Could you give them a try?
I tried kernel-220.127.116.11-62.fc8.i686 but the problem is still here. So i
investigate a little more and it seems that the directive RATE=Auto in
/etc/sysconfig/network-scripts/ifcfg-wlan0 does not work anymore. I need in
place to have RATE=54Mb to obtain a stable connexion. If i let RATE=Auto, i
always have Bit Rate=1 Mb/s with iwconfig.
Hope this will help you ...
Ah, OK...we are seeing a similar problem with upstream kernels. I'll have to
get back to you once we discover the root of the problem...
Some news about this ?
Nothing to report...
The problem is still here in 18.104.22.168-85.fc8.
Ivo, is it possible that rt2x00 is not providing the proper information back
to the rate control algorithms?
John, are the following 3 patches inside the latest FC kernel?
rt2x00: Only update rssi average approximation on receiving beacon frames.
rt2x00: Correctly set ACK bit in tx descriptors
[PATCH] rt2x00: Fix residual check in PLCP calculations.
Not sure about -85.fc8, but all of those are available in -99.fc8:
Eric, can you try the -99.fc8 kernels and report the results back here?
The same. If i put RATE=Auto i obtain Bit Rate=1 Mb/s and the connection is very
slow and i put RATE=54Mb all work fine.
Here it seems to be the same problem with the same solution :
Created attachment 290788 [details]
register dump script
Not sure if it is possible, but is DEBUGFS available in Fedora kernels?
If so, please mount debugfs and run the following script inside the rt2500pci
entry within the mac80211 debugfs entry.
Please do this with both the working kernel and the non working kernel and
store the output in 2 different files.
I can confirm I am having the same problem.
Very slow connection with Rate=Auto, normal/fast connection if I set Rate=54M
I am using kernel -99.fc8
(In reply to comment #16)
> Created an attachment (id=290788) 
> register dump script
> Not sure if it is possible, but is DEBUGFS available in Fedora kernels?
I don't know maybe someone else (John ?) could answer.
> If so, please mount debugfs and run the following script inside the rt2500pci
> entry within the mac80211 debugfs entry.
I don't understand what you mean. Please be more detailed because i'm a newbie
> Please do this with both the working kernel and the non working kernel and
> store the output in 2 different files.
You mean for the working kernel the one before 22.214.171.124-49.fc8 ?
(In reply to comment #18)
> > If so, please mount debugfs and run the following script inside the
> > entry within the mac80211 debugfs entry.
> I don't understand what you mean. Please be more detailed because i'm a
> in kernel.
As root do:
mount -t debugfs /sys/kernel/debug
Then check the contents of /sys/kernel/debug, there should be a ssubdirectory
for your wireless interface if you go in there you find a folder
named "rt2500pci" (it might be several folders deeper).
When you are inside the rt2500pci/register folder, run the attached script and
redirect the output to a new file. Do this for both the working and the
non-working kernel and you will have 2 files, please attach those 2 files to
> > Please do this with both the working kernel and the non working kernel and
> > store the output in 2 different files.
> You mean for the working kernel the one before 126.96.36.199-49.fc8 ?
From your report I understood that the last working kernel was:
And the first broken kernel was: 188.8.131.52-49.fc8
So please test with those 2 kernels.
Of course using a even more recent kernel would also be very nice just in case
the problem has already been resolved. :)
# mount -t debugfs /sys/kernel/debug
Usage: mount -V : print version
mount -h : print this help
mount : list mounted filesystems
mount -l : idem, including volume labels
So either debugfs is not implemented or the command line is not good.
Sorry about that:
mount -t debugfs debugfs /sys/kernel/debug/
Ok now i can mount but in /sys/kernel/debug/ i have only ieee80211, kprobes and
usbmon directories. Under ieieee80211 i have a dir : phy0 and nothing in it.
I tried 184.108.40.206-101.fc8 and the problem is still present.
I installed Kernel 220.127.116.11-101.fc8 and the problem is still there.
Morover I cannot even modify the speed by using iwconfig. It is stuck at 1 Mb/s.
If I start my computer using Kernel 18.104.22.168-99.fc8 then I can still modify the
speed manually with "iwconfig wlan1 rate 54M"
If I modify the wlan configuration file/files and set the rate to 54M, this does
have not effect at all. The only way to modify the speed is by using iwconfig
and by using Kernel -99.f8
The bug seems solved in kernel-22.214.171.124-104.fc8. More test are welcome.
Confirmed. I installed kernel-126.96.36.199-104.fc8 and the speed is now adjusted
automatically depending on the quality of the signal.
Excellent news. :)
Since I have the same problem described in this bug report I tested kernel-
188.8.131.52-104.fc8 too. Unfortunately, my wlan card (using rt61pci) doesn't
associate at all any longer with my wlan router. iwlist wlan0 scan doesn’t show
any access points. I tested kernel-184.108.40.206-105.fc8 too with the same result.
Should I submit a new bug report on this? I don’t know if I’m supposed to do
that on kernels that haven’t been released yet.
Open a new bug.