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On Wed, Feb 6, 2013 at 1:34 PM, Siji Sunny <[email protected]> wrote:
> It seems like the usb controller used* *in Rspberry pi SOC (Broadcom
> BCM2835) has some serious issues , since it can only supply low amount of
> current to its USB devices (Approximately 140 mA). This will cause
> continues restart of RPI specially while connecting USB Network Card, USB
> Modem or GPS devices.
>
> This may be a bug in USB driver, which has not fixed yet and may not be an
> easy task because :
>
> (Ref:
> http://hardware.slashdot.org/story/12/08/24/2228251/serious-problems-with-usb-and-ethernet-on-the-raspberry-pi
> )
>
> 1) Documentation on the Broadcom USB controller is proprietary and is not
> made openly available by the Raspberry Pi Foundation.
>
> 2) The USB core for the Broadcom SoC was bought from a 3rd party, and we
> are told that not even Broadcom has full documentation, nor understands the
> driver.
>
> 3) The Foundation has discovered that the controller and its driver expect
> realtime response from the ARM core, and if Linux's non-realtime scheduling
> doesn't respond in 1 ms, a split transaction USB event can be dropped. Not
> surprisingly, this occurs regularly and produces lost mouse clicks, stuck
> keyboard keys, etc..
>
>
> --
> Siji Sunny
> _______________________________________________
> ILUGC Mailing List:
> http://www.ae.iitm.ac.in/mailman/listinfo/ilugc



-- 
Gayatri Hitech
http://gayatri-hitech.com
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