On Mon, Oct 03, 2005 at 04:44:31PM -0400, Alan Stern wrote: > On Mon, 3 Oct 2005, Christopher Li wrote: > > There is a different way to do it, using sysfs (not usbfs). The "bind" > and "unbind" attributes are still very new, not yet in many distributions. >
OK, I will check it out. I don't think I can count on this new feature though. I can't even count on the usable 64 bit compatible layer in usbdevfs. Most of our supported distribution don't have it yet. > > Even if I use the unbind kernel driver, it is not as good as if kernel > > can provide device level lock out. I still have to worry about the set > > config need to unclaim interface and possible lose the device to kernel/ > > other user space driver. > > Force disconnect and claim it back has side effects who knows what state > > left in the device. > > > > It is likely to confuse the user as well because user expect to solve the > > device ownership issue at connecting the device. In the middle of a working > > section need to solve the device ownership is not very pleasant user > > experience. > > True. > > BTW, why do you need to change the configuration more than once? That's a > rather unusual thing to do. It is the guest VM not me decide what to send. From the guest OS's point of view, it think it owns the devices so it send as many set config as it want. A few case this could happen: - The controller driver reset the device. If the windows reset the port and a sequence of read device descriptor and config descriptor then set config. That usually means it detect some thing serious wrong and trying to desperately recover. - A few devices driver just use set config itself to clean up the device state. - The user disable then enable the device without disconnect it from the VM, reboot etc. - Most webcam will use try different alternate setting to find a max usable bandwidth. It is not exactly set config but it is similar. Chris ------------------------------------------------------- This SF.Net email is sponsored by: Power Architecture Resource Center: Free content, downloads, discussions, and more. http://solutions.newsforge.com/ibmarch.tmpl _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
