Re: hub port power control vs. physical disconnect/connect
"Vlado Handziski" <[email protected]>
| Newsgroups | gmane.linux.usb.devel |
|---|---|
| Message-ID | <[email protected]> |
On Dec 12, 2007 6:15 PM, Alan Stern <[email protected]> wrote: > On Wed, 12 Dec 2007, Vlado Handziski wrote: > > > > On Dec 12, 2007 4:20 PM, Alan Stern <[email protected]> wrote: > > > > > The USB stack doesn't remove a device until it gets a disconnect > > > message from the device's hub. When you turn off the port power the > > > hub doesn't send any disconnect messages, so the kernel doesn't realize > > > the device is gone. > > > > > > Currently there is no way for you to force this behavior (and there is > > > no way to call usb_disconnect from userspace). You can come close by > > > unbinding the device's driver. For example, if the device's sysfs ID > > > was 1-2.3 you would do: > > > > > > echo -n 1-2.3 >/sys/bus/usb/drivers/usb/unbind > > > > > > That won't remove the device structure but it will make the structure > > > almost unusable. > > > > > > > Yes, we are already doing that (as shown in case 2 in the log at the end of > > the original message). I was hoping that there is something more that can be > > done that would either remove the device completely or at least export > > somehow the info to sysfs that the structure below this devce path is stale. > > Right now there isn't anything like that. It could be added if people > really want it. We can track this using internal state. It is not "pretty", but allows us to work around it. I guess the HAL guys in KDE/GNOME must be doing something similar, assuming they support hub port power control at all... Vlado ------------------------------------------------------------------------- SF.Net email is sponsored by: Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://ad.doubleclick.net/clk;164216239;13503038;w?http://sf.net/marketplace _______________________________________________ [email protected] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel