Could not find wireless connection in CentOS 6.2

fastjacksonmin · 10-03-2013, 01:29 PM

Hi, All,

Several days ago, I successfully installed CentOS 6.4 so that I could use Sentaurus, a Device simulator there. However, the software doesn't work properly and I was told that the newest Sentaurus could only support CentOS 6.2.

So I burn another DVD of CentOS6.2 and install again. But this time my desktop cannot find wireless connection and wired connection is always offline somehow in my office. So what could happen when CentOS 6.4 could reach the wireless connection while 6.2 could not?

I checked lspci and did find the wireless network adapter, which is AR9485. This is listed in the CentOS wiki and is supposed OK to go. (http://wiki.centos.org/HowTos/Laptop...78e24128fd2eec)

But when checking iwconfig, no wireless extensions show up.

Code:

# iwconfig
lo            no wireless extensions.
p5p1          no wireless extensions.

I was kind of curious what could happen and would like to ask for some help from you.

Thank you very much for the help!

corp769 · 10-03-2013, 01:36 PM

Did you run modprobe as root? You need to use "sudo" with the modprobe command. Also have a look at both your dmesg and /var/log/messages output for any related warnings and errors.

fastjacksonmin · 10-03-2013, 01:46 PM

Hi,

Thank you for the suggestions.

I did use modprobe as a root, and it did not return any error message when I typed

Code:

# modprobe ipw2200

The following is the message I checked and think might be related to the wireless connection:

Code:

Oct 3 10:09:33  jiemin-LINUX kernel: ipw2200: Intel(R) PRO/Wireless 2200/2915 Network Driver, 1.2.2kmprq
Oct 3 10:09:33  jiemin-LINUX kernel: ipw2200: Copyright(c) 2003-2006 Intel Corporation

Do you have any other suggestions about what I need to check for the messages?

corp769 · 10-03-2013, 02:05 PM

Wait wait... First you are talking about a device simulator, then actual hardware; For the hardware, you started talking about an atheros chipset, then you switch to intel related drivers. Can you please elaborate further as what you are trying to do? I am completely lost; Could you post the output of the following commands for me? Thanks!

Code:

lspci -v
lsmod
ifconfig -a
iwconfig -a
uname -a

fastjacksonmin · 10-03-2013, 02:36 PM

Sorry for the confusion. The device simulator is just a software I want to use in my work. To have that work, I need:
1.An ethernet connection so that I could fetch license from the server and
2.A CentOS 6.2 version which is the newest version the software can support

Previously, I have CentOS6.4 installed, and it could reach the internet through wireless without much effort, but when I installed CentOS6.2, I could not find any available wireless connection. So I was thinking what could happen to cause such a problem.

The first thing I think of is probably the CentOS6.2 could not support the hardware, so I checked the hardware which is AR9485 and is listed in the CentOS wiki. I tried to follow the steps in the wiki but it does not help me to get connected. So I have made sure that CentOS could recognize the adapter, but when checking iwconfig, it does not see any wireless extensions.

The result as requested is as following: (Sorry that I was just typing the codes since I am using another computer to post this thread, so it would be somewhat shortened)

Code:

# lspci -v
...
03:00.0 Network Controller: Atheros Communications Inc. AR9485 Wireless Network Adapter (rev 01)
Subsystem: Dell Device 0208
Flags: bus master, fast devsel, latency 0, IRQ 10
Memory at f7c80000 (64-bit, non-prefetchable) [size=512K]
Expansion ROM at f7c80000 [disabled] [size=64K]
Capabilities: [40] Power Management version 2
Capabilities: [50] MSI: Enable0 Count=1/4 Maskable+ 64bit+
Capabilities: [70] Express Endpoint, MSI 00
Capabilities: [100] Advanced Error Reporting
Capabilities: [140] Virtual Channel <?>
Capabilities: [160] Device Serial Number 00-00-00-00-00-00-00-00

04:00.0 Ethernet controller： Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit ethernet Controller (rev 07)
Subsystem: Dell Device 0581
Flags: bus master, fast devsel, latency 0, IRQ 36
I/O ports at e000 [size=256]
Memory at f0004000 (64-bit, prefetchable) [size=4K]
Memory at f0000000 (64-bit, prefetchable) [size=16K]
Capabilities: [40] Power Management version 3
Capabilities: [50] MSI: Enable: Enable+ Count=1/1 Maskable- 64bit+
Capabilities: [70] Express Endpoint, MSI 01
Capabilities: [b0] MSI-X: Enable- Count=4 Masked-
Capabilities: [d0] Vital Product Data
Capabilities: [100] Advanced Error Reporting
Capabilities: [140] Virtual Channel <?>
Capabilities: [160] Device Serial Number 44-00-00-00-68-4c-e0-00
Kernel driver in use: r8169
Kernel modules: r8169

Code:

# lsmod

Module                  Size  Used by
nls_utf8                1455  1 
fuse                   66285  2 
autofs4                26888  3 
sunrpc                243758  1 
cpufreq_ondemand       10448  4 
acpi_cpufreq            7955  0 
freq_table              4881  2 cpufreq_ondemand,acpi_cpufreq
mperf                   1557  1 acpi_cpufreq
ipt_REJECT              2383  2 
nf_conntrack_ipv4       9506  2 
nf_defrag_ipv4          1483  1 nf_conntrack_ipv4
iptable_filter          2793  1 
ip_tables              17831  1 iptable_filter
ip6t_REJECT             4628  2 
nf_conntrack_ipv6       8748  2 
nf_defrag_ipv6         12182  1 nf_conntrack_ipv6
xt_state                1492  4 
nf_conntrack           79453  3 nf_conntrack_ipv4,nf_conntrack_ipv6,xt_state
ip6table_filter         2889  1 
ip6_tables             19458  1 ip6table_filter
ipv6                  322029  35 ip6t_REJECT,nf_conntrack_ipv6,nf_defrag_ipv6
uinput                  8216  0 
microcode             112594  0 
sg                     30124  0 
dcdbas                  9219  0 
serio_raw               4818  0 
i2c_i801               11231  0 
r8169                  39968  0 
mii                     5271  1 r8169
iTCO_wdt               13662  0 
iTCO_vendor_support     3088  1 iTCO_wdt
xhci_hcd              126293  0 
snd_hda_codec_hdmi     24682  1 
snd_hda_codec_conexant    51107  1 
snd_hda_intel          25548  2 
snd_hda_codec          91845  3 snd_hda_codec_hdmi,snd_hda_codec_conexant,snd_hda_intel
snd_hwdep               6780  1 snd_hda_codec
snd_seq                56591  0 
snd_seq_device          6596  1 snd_seq
snd_pcm                84702  3 snd_hda_codec_hdmi,snd_hda_intel,snd_hda_codec
snd_timer              23057  2 snd_seq,snd_pcm
snd                    70023  13 snd_hda_codec_hdmi,snd_hda_codec_conexant,snd_hda_intel,snd_hda_codec,snd_hwdep,snd_seq,snd_seq_device,snd_pcm,snd_timer
soundcore               8086  1 snd
snd_page_alloc          8630  2 snd_hda_intel,snd_pcm
ext4                  364410  2 
mbcache                 8144  1 ext4
jbd2                   88738  1 ext4
sr_mod                 16228  1 
cdrom                  39771  1 sr_mod
sd_mod                 39488  3 
crc_t10dif              1541  1 sd_mod
usb_storage            49452  0 
ahci                   40455  3 
i915                  545870  2 
drm_kms_helper         33236  1 i915
drm                   230675  3 i915,drm_kms_helper
i2c_algo_bit            5762  1 i915
i2c_core               31276  5 i2c_i801,i915,drm_kms_helper,drm,i2c_algo_bit
video                  21032  1 i915
output                  2505  1 video
dm_mirror              14101  0 
dm_region_hash         12170  1 dm_mirror
dm_log                 10122  2 dm_mirror,dm_region_hash
dm_mod                 81500  8 dm_mirror,dm_log

Code:

# ifconfig -a
lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:12 errors:0 dropped:0 overruns:0 frame:0
          TX packets:12 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:720 (720.0 b)  TX bytes:720 (720.0 b)

p5p1      Link encap:Ethernet  HWaddr D4:BE:D9:DA:A6:87  
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)
          Interrupt:36 Base address:0x8000

Code:

# iwconfig 
lo        no wireless extensions.

p5p1      no wireless extensions.

Code:

# uname -a
Linux jiemin-LINUX 2.6.32-220.el6.x86_64 #1 SMP Tue Dec 6 19:48:22 GMT 2011 x86_64 x86_64 x86_64 GNU/Linux

Thx for the help again!

corp769 · 10-03-2013, 02:46 PM

Ok... So then why are you modprobe'ing an intel driver for an atheros chipset? You need to modprobe the correct driver for your chipset (since an Atheros device is present, not an Intel device). Unless you have another wireless card installed?

fastjacksonmin · 10-03-2013, 02:56 PM

Good question! I am not quite good at software thing so I am not quite familiar with the overall structure of how they work together. But based on the wiki listed here: http://wiki.centos.org/HowTos/Laptop...78e24128fd2eec

Quote:

For the Atheros ath9k driver that ships with CentOS 6 you don't need any special firmware to make the device work. The only thing you need to do is load the ath9k driver on your system.

Code:

modprobe ath9k

And then you can enable NetworkManager to use it.

But nothing happens after I did that. Even no error message is shown. Which I then checked other website and that's where ipw2200 comes out.

Do you have any suggestions about configure it manually then?

Thanks a lot for that

corp769 · 10-03-2013, 03:03 PM

Well ok, before we get too far ahead here... Your original problem is a software issue, and you downgraded to version 6.2 just because of it; Did you do any research about the software issues you were having? I was about to go balls to the wall with the networking issue, but realized that you are using an older, more unsupported version of CentOS (you should always keep up with updates as much as possible!). The issue you are experiencing may be related to a certain change that has been fixed for 6.3+, and all of this may be completely unnecessary.

fastjacksonmin · 10-03-2013, 03:08 PM

Yeah, that's what bothers me a lot.

The Software does not work properly under CentOS 6.4. So I asked the technical guy from that company, and they said that even their newest software can only support version CentOS 6.2! Which drives me back from CentOS 6.4 to CentOS 6.2. I do believe that problem has been solved internally in CentOS6.4 since I did have connection in Version 6.4 era.

corp769 · 10-03-2013, 03:31 PM

Doesn't sound too much like an actual tech guy, but hey... Just my opinion

It could be as simple as a version mismatch, etc, and in which if it was such the case, you would need to either downgrade a library, install a different version (like a backport, different name/structure to have multiple versions installed at the same time, etc). I just want to make sure we troubleshoot what you want to troubleshoot, as usually when a company tells me "that version is unsupported," I usually make it work regardless; I say it like this because the wireless works in 6.4 out of the box, and not 6.2! --> This will be due to older drivers, not the distro itself.

fastjacksonmin · 10-03-2013, 03:40 PM

I guess he just didn't want to waste time. I don't quite like this software because the GUI is really user-hostile. MATLAB is just like a obedient cute maid girl compared to it, but our group has paid for it and it could do some complicated simulation that MATLAB cannot, so we still have to use it.

I do think your suggestion of downgrade a library might help. The problem is I am not sure which library I should turn to. Or I simply downgrade all the library?