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-   -   Weak signal and slow speed with Realtek RTL8185 (https://www.linuxquestions.org/questions/linux-wireless-networking-41/weak-signal-and-slow-speed-with-realtek-rtl8185-785206/)

mawkernewek 01-27-2010 07:54 PM

Weak signal and slow speed with Realtek RTL8185
 
The signal strength on my Realtek RTL8185 wireless networking card is much less than in windows.

In windows it achieves 3 bars out of 5 and works at the full 54Mbps however in OpenSUSE 11.2 it achieves only 13% signal strength and reports a 1Mpbs bitrate.

output of iwconfig:

wlan0 IEEE 802.11bg ESSID:"*****"
Mode:Managed Frequency:2.412 GHz Access Point: 00:24:B2:32:A5:2E
Bit Rate=1 Mb/s Tx-Power=20 dBm
Retry long limit:7 RTS thr:off Fragment thr:off
Encryption key:963F-A499-939C-29A9-D6F3-09ED-EF2E-CF04-4F75-6EDC-714F-BD42-4ABF-6613-80EF-4ACB [2]
Power Management:off
Link Quality=13/100 Signal level=13/100
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0

Moreover the signal strength appears to be spurious since placing aluminum foil over the external antenna does not affect the number given although doing this in windows reduces it from 3 bars to 1 and the speed suffers.

This is using the rtl8180 driver on kernel 2.6.31.5-0.1-default

I have tried to use ndiswrapper to see if using a windows xp driver would work better however blacklisting the rtl8180 driver didn't stop the system from using it.

In fact www.speedtest.net reports the download speed as about 1.5Mbps whether in OpenSUSE 11.2 or on a wired ethernet connection on the netbook.

However an scp from the netbook to the desktop doesn't achieve more than that, so I'm fairly sure the connection between the desktop and router isn't working at full speed.

nimnull22 01-29-2010 06:03 PM

What is other drivers for rtl chipsets this kernel have?

find / -name rtl*.ko

mawkernewek 01-29-2010 06:11 PM

I changed kernel version to 2.6.32-10-generic now

I've got rtl8187se, rtl8187, rtl8180, rtl8150, rtl8187, rtl8180 on that. I've noticed a new version of the drivers have appeared on the realtek website at http://www.realtek.com.tw/downloads/...Downloads=true

so might downgrade back to 2.6.31 and give those a try (wouldn't compile on 2.6.32)

nimnull22 01-29-2010 06:17 PM

Try this driver first.

mawkernewek 01-29-2010 06:21 PM

I tried to compile the driver but failed, which I presume is because 2.6.32 is too new?

root@dlrt2:/home/dlrt2/Download/rtl8...07.2009.release# make
make[1]: Entering directory `/usr/src/linux-headers-2.6.32-10-generic'
CC [M] /home/dlrt2/Download/rtl8185_linux_26.1031.1207.2009.release/rtl8185/r8180_core.o
/home/dlrt2/Download/rtl8185_linux_26.1031.1207.2009.release/rtl8185/r8180_core.c: In function ‘proc_get_stats_hw’:
/home/dlrt2/Download/rtl8185_linux_26.1031.1207.2009.release/rtl8185/r8180_core.c:350: warning: cast from pointer to integer of different size
/home/dlrt2/Download/rtl8185_linux_26.1031.1207.2009.release/rtl8185/r8180_core.c:351: warning: cast from pointer to integer of different size
/home/dlrt2/Download/rtl8185_linux_26.1031.1207.2009.release/rtl8185/r8180_core.c:354: warning: cast from pointer to integer of different size
/home/dlrt2/Download/rtl8185_linux_26.1031.1207.2009.release/rtl8185/r8180_core.c:355: warning: cast from pointer to integer of different size
/home/dlrt2/Download/rtl8185_linux_26.1031.1207.2009.release/rtl8185/r8180_core.c:358: warning: cast from pointer to integer of different size
/home/dlrt2/Download/rtl8185_linux_26.1031.1207.2009.release/rtl8185/r8180_core.c:359: warning: cast from pointer to integer of different size
/home/dlrt2/Download/rtl8185_linux_26.1031.1207.2009.release/rtl8185/r8180_core.c: In function ‘check_tx_ring’:
/home/dlrt2/Download/rtl8185_linux_26.1031.1207.2009.release/rtl8185/r8180_core.c:826: warning: cast from pointer to integer of different size
/home/dlrt2/Download/rtl8185_linux_26.1031.1207.2009.release/rtl8185/r8180_core.c:826: warning: cast from pointer to integer of different size
/home/dlrt2/Download/rtl8185_linux_26.1031.1207.2009.release/rtl8185/r8180_core.c:827: warning: cast from pointer to integer of different size
/home/dlrt2/Download/rtl8185_linux_26.1031.1207.2009.release/rtl8185/r8180_core.c:827: warning: cast from pointer to integer of different size
/home/dlrt2/Download/rtl8185_linux_26.1031.1207.2009.release/rtl8185/r8180_core.c: In function ‘alloc_tx_desc_ring’:
/home/dlrt2/Download/rtl8185_linux_26.1031.1207.2009.release/rtl8185/r8180_core.c:1447: warning: cast from pointer to integer of different size
/home/dlrt2/Download/rtl8185_linux_26.1031.1207.2009.release/rtl8185/r8180_core.c:1447: warning: cast to pointer from integer of different size
/home/dlrt2/Download/rtl8185_linux_26.1031.1207.2009.release/rtl8185/r8180_core.c: In function ‘alloc_rx_desc_ring’:
/home/dlrt2/Download/rtl8185_linux_26.1031.1207.2009.release/rtl8185/r8180_core.c:1621: warning: cast from pointer to integer of different size
/home/dlrt2/Download/rtl8185_linux_26.1031.1207.2009.release/rtl8185/r8180_core.c:1621: warning: cast to pointer from integer of different size
/home/dlrt2/Download/rtl8185_linux_26.1031.1207.2009.release/rtl8185/r8180_core.c: In function ‘rtl8180_rx’:
/home/dlrt2/Download/rtl8185_linux_26.1031.1207.2009.release/rtl8185/r8180_core.c:2065: error: implicit declaration of function ‘rdtsc_rtl’
/home/dlrt2/Download/rtl8185_linux_26.1031.1207.2009.release/rtl8185/r8180_core.c: In function ‘rtl8180_watch_dog’:
/home/dlrt2/Download/rtl8185_linux_26.1031.1207.2009.release/rtl8185/r8180_core.c:2793: warning: unused variable ‘bEnterPS’
make[2]: *** [/home/dlrt2/Download/rtl8185_linux_26.1031.1207.2009.release/rtl8185/r8180_core.o] Error 1
make[1]: *** [_module_/home/dlrt2/Download/rtl8185_linux_26.1031.1207.2009.release/rtl8185] Error 2
make[1]: Leaving directory `/usr/src/linux-headers-2.6.32-10-generic'
make: *** [all] Error 2

nimnull22 01-29-2010 06:23 PM

You have already rtl8180. Try it. Type:
modprobe -r rtl8180
modprobe rtl8180
dmesg | tail -n 50

Post output, but cat only about driver.

mawkernewek 01-29-2010 06:27 PM

the relevant lines seem to be:

[21786.061352] rtl8180 0000:03:06.0: PCI INT A disabled
[21794.967150] rtl8180 0000:03:06.0: PCI INT A -> GSI 20 (level, low) -> IRQ 20

mawkernewek 01-29-2010 06:30 PM

I also get:

[21795.117487] phy0: Selected rate control algorithm 'minstrel'

which seems to refer to the bit rate control.

As I understand it, the problem is that the rtl8180 driver makes it report a low signal strength for whatever reason and that makes it slow down?

nimnull22 01-29-2010 06:39 PM

That is not all, can post full output through http://pastebin.com/.

mawkernewek 01-29-2010 06:39 PM

A file transfer running from my netbook (which AFAIK wireless works fine on) to desktop begins at 2MB/s but the transfer rate quickly drops to a little over 100kB/s.

mawkernewek 01-29-2010 06:42 PM

http://pastebin.com/m58270479

nimnull22 01-29-2010 06:57 PM

Can you please do:
modprobe -r rtl8180
modprobe rtl8180
dmesg | tail -n 50

Thanks

mawkernewek 01-29-2010 07:19 PM

output of dmesg | tail -n 50 is at http://pastebin.com/m6122d8e6

also when I tried to compile Realtek's linux drivers downloaded from their website I got http://pastebin.com/m42c436f2

nimnull22 01-29-2010 07:29 PM

Have you tried to connect to other AP, just to check you wireless behavior.

Also check your AP settings, may be it is trying to do something that only windows like.
I meant AP wireless settings.

mawkernewek 01-30-2010 02:36 AM

The only other thing I was able to try with the desktop is to set up an ad-hoc network between it and the netbook. This brought the error message (on the desktop):

sudo iwconfig wlan0 mode ad-hoc
Error for wireless request "Set Mode" (8B06) :
SET failed on device wlan0 ; Operation not supported.

I doubt the router (Netgear dgn2000) is doing anything Linux doesn't like since my linux netbook works OK on it. The only thing is the signal strength seems to drop off fairly rapidly.


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