Downgrade GSM/UMTS module to USB 2.0 Fullspeed

Oliver Graute oliver.graute at gmail.com
Thu Jan 19 03:49:09 EST 2017


On 18/01/17, Greg KH wrote:
> On Wed, Jan 18, 2017 at 05:05:34PM +0100, Oliver Graute wrote:
> > Hello list,
> > 
> > i'am using a GSM/UMTS Module on a PCB which is connected with USB 2.0
> > Hi-Speed to my imx6ul CPU. To reduce our Electromagnetic compatibility
> > and to make my hardware colleges happy again I want to downgrade to USB
> > Full Speed.
> > 
> > How can I tell the Linux Kernel to Do so?
> 
> You can't.  It's up to the device to tell the host what "speed" it is
> running at.  See the USB spec for all of the crazy details.
> 
ok thx for this important hint

> I suggest you modify the firmware of your modem to do this, that's the
> only way it is going to work (note, your device needs to be able to
> support full speed, it might not be able to do that.)

I know that the cinterion gsm module support full speed. I have to check their
docs how to force the module into fullspeed.

Best Regards,

Oliver



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