Re: [linux-usb-devel] 2.6.20-rc4: usb somehow broken

[Alan Stern <stern@rowland.harvard.edu>]

On Mon, 15 Jan 2007, Oliver Neukum wrote:

> Am Sonntag, 14. Januar 2007 20:47 schrieb icxcnika@mar.tar.cc:
> > > Can anyone suggest another approach?
> > >
> > > Alan Stern
> > 
> > Just a thought, you could use both a blacklist approach, and a module 
> > paramater, or something in sysfs, to allow specifying devices that won't 
> > be suspend and resume compatible.
> 
> Upon further thought, a module parameter won't do as the problem
> will arise without a driver loaded. A sysfs parameter turns the whole
> affair into a race condition. Will you set the guard parameter before the
> autosuspend logic strikes?
> Unfortunately this leaves only the least attractive solution.

There could be a mixed approach: a builtin blacklist that is extensible 
via a procfs- or sysfs-based interface.

Note that we actually have two problems to contend with.  Some devices
must never be autosuspended at all (they disconnect when resuming), and
others need a reset after resuming.

Alan Stern