On Thu, Oct 10, 2002, Oliver Neukum <[EMAIL PROTECTED]> wrote: > > > I think the big remaining question right now is determining how a > > configuration should be elected. > > > > In my devfs patch a long time ago, I had created an election process > > where drivers could specify the priority of their support. The highest > > priority won. > > > > Here's the thought process I originally used: > > - Multiple configurations are rare > > - Devices won't change substantially between configurations (ie won't go > > from a keyboard to a cdrom) > > That is very likely an invalid assumption. > A device might go from webcam to storage, just to give an example.
That's kind of the point, there is no best choice in that case that we can make either through the core, or through a driver. If that's the case, a driver has no business changing the configuration and the core would only change if it really feels it knows better and only at enumeration time. In that case, it's more like setting the configuration rather than changing it (ie some drivers won't be bound to an interface and then kicked off) > > - Used typically to provide different levels of support depending on bus > > or host limitations (ie config for lower power, config for generic > > printer class, but another one for a superset ala uss720) > > > > If that's the case, a priority would probably work well. > > > > Can anyone think of a reason to use different configurations outside of > > what I was thinking? > > No problem. > IMHO selecting a configuration is a policy decision and should be left > to user space. That's prefectly reasonable. Should we just use the first configuration when a device is plugged in? > > Understood. > > > > This also brings up the question of if we should allow the configuration > > to change miduse (meaning after drivers have bound already to any > > interfaces)? > > Why not ? We have no problems with devices being unplugged. > Why should reconfiguration be any different ? Because a user may not have told the system to change the configuration? If the change was made directly because of a user decision, I have no problem with it. JE ------------------------------------------------------- This sf.net email is sponsored by:ThinkGeek Welcome to geek heaven. http://thinkgeek.com/sf _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
