Furthermore, if u look at the /sys/bus/usb interface: . ./uevent ./devices ./devices/usb1 ./devices/1-0:1.0 ./devices/usb2 ./devices/2-0:1.0 ./devices/1-1 ./devices/1-1:1.0 ./devices/2-1 ./devices/2-1:1.0 ./devices/1-1.1 ./devices/1-1.1:1.0 ./devices/1-1.2 ./devices/1-1.2:1.0 ./devices/1-1.3 ./devices/1-1.3:1.0 ./devices/1-1.4 ./devices/1-1.4:1.0 ./devices/1-1.5 ./devices/1-1.5:1.0 ./devices/1-1.5:1.1 ./devices/2-1.2 ./devices/2-1.2:1.0 ./devices/2-1.3 ./devices/2-1.3:1.0 ./devices/2-1.6 ./devices/2-1.6:1.0 ./drivers ./drivers/usbfs ./drivers/usbfs/module ./drivers/usbfs/uevent ./drivers/usbfs/unbind ./drivers/usbfs/bind ./drivers/usbfs/new_id ./drivers/usbfs/remove_id ./drivers/usbfs/1-1.3:1.0 ./drivers/hub ./drivers/hub/module ./drivers/hub/uevent ./drivers/hub/unbind ./drivers/hub/bind ./drivers/hub/new_id ./drivers/hub/remove_id ./drivers/hub/1-0:1.0 ./drivers/hub/2-0:1.0 ./drivers/hub/1-1:1.0 ./drivers/hub/2-1:1.0 ./drivers/usb ./drivers/usb/uevent ./drivers/usb/unbind ./drivers/usb/bind ./drivers/usb/usb1 ./drivers/usb/usb2 ./drivers/usb/1-1 ./drivers/usb/2-1 ./drivers/usb/1-1.1 ./drivers/usb/1-1.2 ./drivers/usb/1-1.3 ./drivers/usb/1-1.4 ./drivers/usb/1-1.5 ./drivers/usb/2-1.2 ./drivers/usb/2-1.3 ./drivers/usb/2-1.6 ./drivers/usb-storage ./drivers/usb-storage/1-1.1:1.0 ./drivers/usb-storage/module ./drivers/usb-storage/uevent ./drivers/usb-storage/unbind ./drivers/usb-storage/bind ./drivers/usb-storage/remove_id ./drivers/usb-storage/2-1.2:1.0 ./drivers/usbhid ./drivers/usbhid/1-1.2:1.0 ./drivers/usbhid/module ./drivers/usbhid/uevent ./drivers/usbhid/unbind ./drivers/usbhid/bind ./drivers/usbhid/new_id ./drivers/usbhid/remove_id ./drivers/uvcvideo ./drivers/uvcvideo/1-1.5:1.0 ./drivers/uvcvideo/1-1.5:1.1 ./drivers/uvcvideo/module ./drivers/uvcvideo/uevent ./drivers/uvcvideo/unbind ./drivers/uvcvideo/bind ./drivers/uvcvideo/new_id ./drivers/uvcvideo/remove_id ./drivers_probe ./drivers_autoprobe this I guessed account for some of the hardware (like USB mass storage device) still working, whereas those that depend on the /dev/bus/usb interface is not working (eg, Android's adb) another symptom is that when i "mkdir -p /dev/bus/usb" directory, by inserting a new USB harddisk, the directory is immediately deleted. and now i can access the newly inserted harddisk, and dmesg returns: [26949.222877] sd 12:0:0:0: [sdc] Mode Sense: 38 00 00 00 [26949.225095] sd 12:0:0:0: [sdc] No Caching mode page present [26949.225099] sd 12:0:0:0: [sdc] Assuming drive cache: write through [26949.230715] sd 12:0:0:0: [sdc] No Caching mode page present [26949.230719] sd 12:0:0:0: [sdc] Assuming drive cache: write through [26949.282965] sdc: sdc1 sdc2 sdc4 [26949.288972] sd 12:0:0:0: [sdc] No Caching mode page present [26949.288977] sd 12:0:0:0: [sdc] Assuming drive cache: write through [26949.288980] sd 12:0:0:0: [sdc] Attached SCSI disk seemingly noproblem - but "lsusb" returned NOTHING. In fact I had also mirror the entire system into another different hardware - before the /dev/bus/usb non-availability happened, and this same system is still working fine. So I am quite sure it is a udev thing, just trying my luck if anyone know the answer? On Sat, Sep 29, 2012 at 9:42 AM, Peter Teoh <htmldeveloper@gmail.com> wrote:
I entered "lsusb" at the command line (as root) and nothing is return, not even any error message.
Doing a strace the last few lines are:
open("/dev/bus/usb", O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC) = -1 ENOENT (No such file or directory) open("/proc/bus/usb", O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
What happened?
This is Ubuntu 10.04 (it used NOT to be like that, not sure I what did wrong last time). But running a VirtualBox INSIDE this same OS, I was able to get result from "lsusb" (after enabling the USB devices in VirtualBox interface) and strace gives result:
open("/dev/bus/usb/001/002", O_RDWR) = 3 ioctl(3, USBDEVFS_IOCTL, 0xbff6f75c) = -1 ENOTTY (Inappropriate ioctl for device) close(3) = 0 open("/dev/bus/usb/001/001", O_RDWR) = 3
Why the difference?
-- Regards, Peter Teoh
-- Regards, Peter Teoh