Re: PXA27x UDC Power

[Oliver Neukum <oliver@xxxxxxxxxx>]

Am Mittwoch 28 November 2007 schrieb Justin Clacherty:
> Hi,
> 
> We've got a PXA27x system using the pxa27xudc driver to talk to a 
> desktop via CDC.  The device also recharges its battery using USB power 
> and requires more than 100mA to do this.
> 
> The CDC driver reports that it is using/requires 100mA.  Looking through 
> the code I haven't been able to find out how I tell the host I want more 
> power.  I also can't find anywhere that tells me that the host can 
> supply 500mA (ie. I'm not on an unpowered hub).

The power needs are listed in a descriptor per configuration.

> How do I tell the host I want more?  I could hack the configuration in 
> ether.c but I figured this really wasn't a nice way to do it and that 
> there was most likely a better way.
> 
> How do I tell if the host can supply more than 100mA?

You cannot. The canonical way to support this is to provide two
configurations, identical except for power use.

	Regards
		Oliver

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