On Sat, 24 May 2014, vichy wrote: > hi Alan: > > 2014-05-23 22:34 GMT+08:00 Alan Stern <st...@rowland.harvard.edu>: > > On Fri, 23 May 2014, vichy wrote: > > > >> hi all: > >> Sorry for not making my description more clearer. > >> in ehci controller, > >> 1. is it possible to know the period bandwidth in a frame from sys or > >> other additional configuration? > > > > The information is available in debugfs, in > > /sys/kernel/debug/usb/ehci/.../bandwidth. > > > >> 2. is it possible to know how many bits in SMASK and CMASK are > >> assigned to 1 in a frame? > > > > Do you mean how bits in SMASK and CMASK are set to 1 in a QH or sITD? > YES > > The SMASK and CMASK values are provided in > > /sys/kernel/debug/usb/ehci/.../periodic. > > > Below is the directory content under /sys/kernel/debug/usb > And I cannot see ehci directory. > My kernel version is Linux 2.6.38-8-generic. > Should I recompile kernel with additional configuration?
You need to enable CONFIG_USB_DEBUG. Also, the /sys/kernel/debug/usb/ehci/.../bandwidth file wasn't added until 3.13, so you won't see it in 2.6.38. > # ls /sys/kernel/debug/usb/ > devices usbmon > # > > appreciate your kind help Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
