Re: USB devices fail unnecessarily on unpowered hubs

[Mark Lord]

Andrew Morton wrote:
> On Thu, 01 Jun 2006 02:18:20 -0700
> ..
> > This is generating a lot of grief and appears to be unnecessarily
> > strict. Common USB sticks with a MaxPower value just above 100mA, for
> > instance, typically work fine on unpowered hubs supplying 100mA.
> >
> > Is a more user-friendly solution possible? Could the shortfall
> > information be passed to udev, which would allow rules to be written per
> > device?
..
> Yes, it sounds like we're being non-real-worldly here.  This change
> apparently broke things.  Did it actually fix anything as well?

I think a far more sensible approach would be to just ensure that the
total current draw for the (unpowered) hub and all connected devices,
stays below the 500mA allowed.  So a 200mA device could coexist with
a 100mA device on a hub which itself steals 100mA.

Cheers
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