Detecting USB devices at startup?

[Krassimir Slavchev]

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Hi,

M. Warner Losh wrote:
> In message: <472F1A97.3090308 at bulinfo.net>
>             Krassimir Slavchev <krassi at bulinfo.net> writes:
> : At boot I get:
> ::: doesn't
> : But if I unplug and plug the usb device:
> ::: works
> : Any ideas why this happens?
> : PS1: I have this problem with all USB devices I tested.
> 
> This may be a power issue.  I've been running a KB2902A for months
> with -current with various types of ucom devices that are seen at
> boot without the hotplug.
> 
> Maybe you can try adding a powered hub and seeing if that helps.
> 
> Warner
> 

Yes, It looks like a power issue but the power supply used in the
development board is very good designed (LM2576 is used). I will measure
power line again. Also the PWM frequency might interfere with PLL.
I will try to find powered hub to make tests. All usb hubs on the market
are bus-powered :(


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