2009-04-06 10:34:12     USB Ethernet Gadget g_ether failure when Frequency Scaling

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2009-04-06 10:34:12     USB Ethernet Gadget g_ether failure when Frequency Scaling

Michal Steyn (AUSTRIA)

Message: 72259   

 

I am working on a project that requires a high level of power management.

 

In order to accomplish this both frequency scaling and placing the CPU in Standby is used.

 

 

The system also uses the RNDIS, Ethernet over USB Gadget (g_ether).

 

 

However, the second the cpu core frequency is lowered from the normal 500 MHz, to 250 MHz or 125 MHz, the Ethernet link starts to fail. Pining the device from a host pc results with a "General Failure".

 

 

If the core frequency is changed back to 500 MHz, the gadget continues to fail, until the USB cable is unplugged and reinserted, or the module is unloaded and reloaded.

 

 

Is this a limitation, that the gadget will only work when the CPU core frequency is on max?

 

 

Is there anything that needs to be set / changed / configured in order to allow the gadget to work?

 

 

I am using a BF548 chip, the kernel is: Linux release 2.6.22.19-ADI-2008R1.5-svn1810, build #965 Mon Apr 6 13

:56:35 SAST 2009

 

 

Regards,

Michal

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