Red Hat Bugzilla – Bug 436285
iwlist scan returns no results for rt73 usb
Last modified: 2008-05-13 14:40:26 EDT
Description of problem:
I can not scan for APs with rt73 usb wireless device. There are three APs
around, all of them are properly seen by an internal intel wireless.
Version-Release number of selected component (if applicable):
Linux gopher 22.214.171.124-18.fc8 #1 SMP Tue Mar 4 21:14:18 EST 2008 x86_64 x86_64
Steps to Reproduce:
1. Insert the rt73 usb wifi adapter
2. ifconfig wlan0 up
3. iwlist wlan0 scan
[root@gopher Module]# iwlist wlan0 scan
wlan0 No scan results
Same thing happens with driver from serialmonkey.com. Attaching output that was
appended to dmesg when the driver was loaded with debug=255.
Created attachment 297034 [details]
dmesg; when doing a iwlist scan
Created attachment 297037 [details]
log before iwlist scan
For sake of completeness; this happens before iwlist scan after I connect the
The output you have attached does not seem to come from the in-kernel drivers
for that hardware. Are you using the serialmonkey drivers? Can you replicate
the problem using the in-kernel drivers?
Yes, I can replicate the very same problem with in-kernel driver. I just can not
replicate the debug output :)
This should be fixed in rt2x00 2.1.4 which was released a few minutes ago.
Ivo: thanks for the response.
I created a patch that replaces rt2x00 directory with a git snapshot (it was one
commit after official 2.1.4) and rebuilt the kernel package 126.96.36.199-22.fc8 with
it. Nothing changed; iwlist scan still produces no results, while the other
interface detects 4 access points.
What can I do to gather more information to debug this problem.
There is an official kernel update:
Could you try that one instead?
Many people have reported great success with that one -- please try it.
If it works for you, please note it here as well:
Same behavior with that kernel.
(148f:2573 Ralink Technology, Corp. RT2501USB Wireless Adapter)
There have been lots of important rt2x00 fixes over the past three weeks.
Would you mind (again) trying a later kernel?
Does that improve the situation?
John: Pardon me for delaying the reply that much -- I was struggling to get some
useful debugging information, but kdump doesn't work for me (another bug for
After "ifconfig up" the rt73usb task (or some with similar name, I don't
remember precisely) consumes 100% CPU time. While system was still more-or-less
responsive I removed the hardware and it resulted in no other task being able to
get a CPU share, system seemed frozen. SysRq worked, but I was not able to get a
kdump due to a another problem with kexec/kdump.
Is there any way I can get some useful debugging information until kexec gets
fixed? Will output of some SysRq hotkey (before unplugging the hardware) be of
The problem in comment 11 should be resolved by -82.fc8 and later. Could you
try these kernels?
Do they resolve the issue for you?