On Sat, Jun 14, 2014 at 10:58:53AM +0800, Simon Guo wrote: > Forward to USB mail alias for the USB question. > > -------- Original post -------- > Subject: Question about USB hotplug > Date: Sat, 14 Jun 2014 09:59:45 +0800 > Sender: Simon Guo <wei.guo.simon@xxxxxxxxx> > Receiver: kernelnewbies@xxxxxxxxxxxxxxxxx, wei.guo.simon@xxxxxxxxx > > Hi, dear list, > > I want to be clear about the USB hotplug procedure. > > I read "Linux Device Driver" and "Documentation/usb/hotplug.txt", and > google much. Per my understanding, the USB hotplug works as following: > 1) Insertion of physical U-disk will trigger a hardware interrupt. And > interrupt handler (installed by USB bus driver?) will create kobj at /sys. > 2) According to Linux device model, the creation of kobj will raise > hotplug event (implemented in USB bus driver). > 3) user space hotplug helper is invoked to handle hotplug event. Hotplug > helper will read "modules.usbmaps" and decide to load which USB driver. > If there are many drivers matching the device, they will all be loaded? > 4) udev will create approparite dev under /dev according to rules defined. > Please correct me if I am wrong in the above. > > I am using Ubuntu 11, and with my own build kernel version 3.15.0. Please ask on a Ubuntu mailing list, they are the only distro that people have problems with this, so they must be doing something "odd" compared to everyone else. sorry, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
