Problem with changing the transmission power (txpower)

Yaoyao Gu guy at
Tue Nov 15 16:12:26 EST 2005


I am really new to this community. So please let me know if this topic has been well discussed before.  I am using Linksys wcf12 wireless cf card. The version of the hostap driver is 0.2.5. I met some problem when I tried to reduce the transmission power of the cf wireless card.

When I execute the following commands, it gives me the error message such as "no private ioctl supported".
$ iwpriv wlan0 prism2-param 5 1  //change the alc to auto control 
                                                    // I have also tried 0 value here 
                                                    // but it generates the same error later
$ iwpriv wlan0 prism2-param 6 103  // set the tx power to 103  

I have also tried $iwconfig wlan0 txpower 103, and it gives me the following message. I guess it's the same problem.
Error for wireless request "Set Tx Power" (8B26) :
SET failed on device wlan0 ; Operation not supported.Several possible reason I can guess: 1) The cf card doesn't support transmission power control. 2) The version of hostap I have doesn't support txpower.

I checked $ iwpriv and it gives a list of parameters that iwpriv can control.  I didn't find txpower in it. But alc is there. I think that's why I can change alc setting. So does that mean that the hostap doesn't support txpower in the current version. If that's the case, how can I solve this problem? Do I need to modify the driver by myself? 

Thanks in advance. Any thoughts or suggestions are highly appreciated.


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