On Wed, 13 May 2009, Brad Schick wrote: > On 05/13/2009 01:13 PM, Alan Stern wrote: > >> It would still > >> be nice to have a good way to correlate the logs beyond manually > >> matching up requests and responses. > >> > > > > I'm not sure how that could be done. usbmon runs at a layer where > > there's no particular information about the origin of an URB. > > Detailed comparison of timestamps, perhaps? But remember, the kernel > > logs generally aren't intended for automatic analysis; they are meant > > to be read manually. > > > > Yes, timestamps would be a great help. Don't say "would" -- your logs already contain high-precision timestamps. For example, in this usbfs_snoop entry: > May 13 11:47:53 wegos-desktop kernel: [69330.277838] usb 1-1.1.2: urb complete the 69330.277838 is a timestamp. And in the corresponding line from the usbmon log: > f33e4e00 1298424607 C Ci:1:057:0 0 18 = 12010002 ff00ff40 25098190 10000000 0001 the 1298424607 is also a timestamp (in microseconds). The two values are offset from one another but the offset shouldn't change over the course of your test. > I have different firmware with a more complex device descriptor (more > interfaces and endpoints), that goes through 6 resets. Have you seen > Windows OS perform that many resets during enumeration? Not that I can remember. Maybe some of the resets occur after enumeration? But I guess that would depend on your driver program. > Anyway, its good to have an answer. The reason this is an issue to start > with is that the firmware and the host app aren't designed to account > for resets in the middle of "in" transfers. The device just doesn't have > the SRAM or the code size to buffer much. Normally not a problem since > resets seem rare, but with vmware/guest running the resets often come > after Linux has finished enumeration and started interrupt-in requests. > At least I know what to lookout for, if I get tech support calls on this > someday. Isn't is possible to configure VMware so that it will leave USB devices alone, not attempt to virtualize them? > Thank you again for all the feedback Alan. Very much appreciated! You're welcome. Alan Stern -- 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
