Re: [linux-usb-devel] [PATCH] USB: Only enable autosuspend by default on certain device classes

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

On Fri, 3 Aug 2007, Matthew Garrett wrote:

> On Thu, Aug 02, 2007 at 06:15:05PM -0700, Greg KH wrote:
> 
> > Well, if you do this, then you can pretty much delete the whole quirk
> > table we have, right?
> 
> At the moment, yes.
> 
> > And personally, I want to do better than Windows XP when it comes to
> > power management.  This patch is only going to suspend a very tiny
> > subset of devices, including a whole bunch of ones that do not even have
> > drivers in Linux, causing our power footprint to be bigger than needed.
> 
> I agree. I'd much rather see us suspending devices whenever possible - 
> it's just that I have concerns over the scalability of the blacklist, 
> given the number of devices that seem to have issues.

While I agree in general, perhaps a different approach would work
better.  For instance, we could blacklist a few known-bad device
classes (maybe even using the existing blacklist) rather than
whitelisting a few known-good ones -- or trying to blacklist each 
member of the bad classes!

Also, building something this sweeping into a kernel driver feels like
a mistake.  It ought to be more easily configurable from userspace, say
via a sysfs file.  Although this wouldn't be so important if we take
the blacklist-classes route.

Alan Stern

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