On Mon, 26 Feb 2007, Jon Smirl wrote: > On 2/26/07, Greg KH <[EMAIL PROTECTED]> wrote: > > But why in the world would we care? These busses can come and go in any > > number of varied and different ways. If you try to rely on a bus id > > then you are going to be wrong eventually. > > The problem is that usbmon is bus number oriented. When I boot my bus > numbers get randomly assigned so I have to manually look for where my > EHCI bus ended up before monitoring on it. > > Is the problem in the way usbmon is designed? Maybe it should just > lump all USB traffic together into one stream and then filter it in > user space.
That's one of the features of the new usbmon update. It adds a "bus 0" which contains all the traffic on all the real buses. Kind of like specifying or not specifying a particular network interface to tcpdump. > usbmon has another flaw in that you can't tell what devices the > streams are for. When the usbmon device is opened it needs to > enumerate the descriptors on everything like lsusb does. That will > cause the descriptor traffic to get recorded in the monitor stream and > allow wireshark to do device/class specific decoding. It doesn't > matter if this enum happens in usbmon or libpcap, the results just > need to end up in the captured stream. Do it in userspace, i.e., libpcap. It's not a kernel issue. > I'd vote for getting rid of the text mode interface to usbmon and > replace it with a tiny app which decodes the binary interface. You > could then give the app a device or class ID and it would filter the > output. Now there's no need for a bus oriented interface. Rather wasteful to transfer all that information from the kernel to userspace and then ignore it. What we really need is some sort of USB packet filter facility for usbmon. Alan Stern ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
