Hi Greg, On 02/09/2012 05:53 PM, Greg KH wrote: > On Thu, Feb 09, 2012 at 11:40:16AM +0530, Abhijit Pawar wrote: >> Hi , >> Is there any way we can get the class type of the attached USB device through >> struct usb_device in a kernel module? >> >> I tried getting the device descriptor and interface descriptor and then use >> them to get the Device and Interface Class and Subclass. >> >> struct usb_device_descriptor *descriptor =&usbDev->descriptor; >> >> struct usb_interface_descriptor *idesc = to_usb_interface(usbDev); >> >> Whenever I run my kernel module, I get 0 for DeviceClass and Interface Class. I >> checked the meaning and it says its the information and to be gathered through >> interface. > That is correct, look at the interface pointer given to your driver. > >> Am I missing something here? What I want is to get the mount point / device >> path of the USB devices. Like for Storage Device I would like to get its mount >> path and for HID I would like to get its device path. > Both of those things make no sense within the kernel, and you will not > be able to detect them from your driver, especially as it is not your > driver bound to this type of device, the in-kernel drivers are. Also, > these have nothing to do with the class type of a device's interface. Yes. As I am dealing with USB Core, I am not in a position to get the interface directly. However I checked the usb_dump_interface_descriptor( ) from usb/core/devices.c and it gives the interface class ( 8 for Storage) correctly. Isnt it forwared to my module which is relying on the linux usb notifier chain? This chain gives me the device pointer and I am trying to enumerate its interface to know its class. > > What are you trying to solve here that you feel you need this > information that is easily found from userspace? I am trying to use USB notifier chains to get the device details and then find out its mount path ( in case of Storage). Are you saying that I should be looking into sysFS and udev rules for getting this mount path? > greg k-h _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
