On Tue, 11 Jan 2011, loody wrote: > hi all: > I found when debug compile option opened, usb driver will create ehci > folder and 3 files, > period, registers and async. > They seems work like usbmon as explaind in ehci.txt in usb document. No, they do not work like usbmon. They contain internal debugging information about the state of the EHCI controller and driver. > But when I try "cat async > /mnt/async.log" after plug in usb flash, > the log shows nothing. > but i did see the content when I "cat registers". > Is there any setting or document I have to check first or the content > of async will only show when I plug special device? The "async" file is non-empty only when there are control or bulk transfers in progress. The "periodic" file is non-empty only when there are interrupt or isochronous transfers in progress (roughly speaking). 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
