On Tue, Apr 24, 2012 at 10:14:05AM -0400, Alan Stern wrote: > In drivers/usb/core/hub.c, look through the hub_events() routine. > There are several function calls similar to this one: > > ret = hub_port_status(hub, i, > &portstatus, &portchange); > > Here i is the port number. This asks the hub to send back status and > change information for port i. (See also the code for the > hub_port_status() and get_port_status() routines.) Thanks, I get it. On Tue, Apr 24, 2012 at 07:52:44PM +0530, anil wrote: > The USB specification Table 11-13 describes the hub descriptor in > detail. > The following data structure struct usb_hub_descriptor defined in > "drivers/usb/core/hub.h" of Linux Kernel source contains information > about the hub descriptor, > > struct usb_hub_descriptor { > _u8 bDescLength; > _u8 bDescriptorType; > _u8 bNbrPorts; > _le16 wHubCharacteristics; > _u8 bPwrOn2PwrGood; > _u8 bHubContrCurrent; > } > > The bNbrPorts member contains information on the number of > downstream-facing ports the hub supports. The structure which i have > provided is in reference to Linux Kernel Version 2.6 series for Linux > Kernel Version 3.0+, Please consult an expert. > Is this information you wanted? > Yes, It is want I wanted.But maybe "11.5.3.1 Labeling" show more footprint. Thanks, all guys. All you give me a very good explanation about the sentence below: "High quality support from experts available instantly over the Internet at no charge has played a major role in stitching together a huge Linux community" which come from the <<Essential Linux Device Drivers>>. Cheers. Udknight -- 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