Re: [linux-usb-devel] Re: OHCI problems with suspend/resume

[David Brownell <david-b@pacbell.net>]

Pavel Machek wrote:
> Hi!
> 
> 
>>>>I'm not sure how the design is intended to work, but either way something 
>>>>needs to be fixed.
>>
>>Yes, it seems like all the HCDs (and the hub driver) need attention.
> 
> 
> Why the hub driver?
> 
> For basic functionality, you simply power it down (doing virtual
> unplug), and power it back up on resume (doing virtual plug of all
> devices). That should work reasonably for everything but mass-storage.

For non-basic functionality such as "remote wakeup", where you
can wake the system up from its suspension by doing things like
typing on the USB keyboard.


>>Plus, the enumeration process should respect hubs' power budgets,
>>and handle overcurrent better.  I had a hub re-enumerate over forty
>>times not that long ago, just because it enabled too many things at
>>once and the surge currents made lots of trouble.  Plenty of power,
>>if it got turned on carefully enough... :)
> 
> 
> Havin enough juice in "common case", but not in "worst case" is not
> too legal situation, is it?

This was a perfectly legal configuration, with what I recall as
four devices.  It was pretty far from "worst case".

- Dave