Neo Sound and USB Questions
bmidgley at gmail.com
Fri Aug 17 21:45:51 CEST 2007
> But most of them just power the 5V line. This is bad with 99% of the bad
> behaving usb gadgets out there.
> But Neo is prolite and asks the host if it could draw it's 500mA and if
> not only takes 100mA out of the bus.
this excessive politeness rules out hand-crank charger, solar cell,
battery-to-usb, and every auto-usb adapter out there. It's overkill.
the usb spec requires the hub to reply to the request for more power.
no reply within xx ms means there is no hub to ask. At this point it
should be pragmatic and just use the @#&* 500mA.
I tried to hunt this down in the source and I think it's in two
places--uboot when off and the kernel when on. It was very hard to
figure out who drives the control.
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