usbmon: drop bogus 0t from usbmon.txt

[linux-2.6-omap-h63xx.git] / Documentation / usb / usbmon.txt

diff --git a/Documentation/usb/usbmon.txt b/Documentation/usb/usbmon.txt
index 53ae866ae37b7e238c8d132783e63102a24ef331..270481906dc80d1b25a0c29f607ef55e83ae16be 100644 (file)
--- a/Documentation/usb/usbmon.txt
+++ b/Documentation/usb/usbmon.txt
@@ -34,9 +34,13 @@ if usbmon is built into the kernel.
 Verify that bus sockets are present.
 
 # ls /sys/kernel/debug/usbmon
-1s  1t  1u  2s  2t  2u  3s  3t  3u  4s  4t  4u
+0s  0u  1s  1t  1u  2s  2t  2u  3s  3t  3u  4s  4t  4u
 #
 
+Now you can choose to either use the socket '0u' (to capture packets on all
+buses), and skip to step #3, or find the bus used by your device with step #2.
+This allows to filter away annoying devices that talk continuously.
+
 2. Find which bus connects to the desired device
 
 Run "cat /proc/bus/usb/devices", and find the T-line which corresponds to
@@ -56,6 +60,10 @@ Bus=03 means it's bus 3.
 
 # cat /sys/kernel/debug/usbmon/3u > /tmp/1.mon.out
 
+to listen on a single bus, otherwise, to listen on all buses, type:
+
+# cat /sys/kernel/debug/usbmon/0u > /tmp/1.mon.out
+
 This process will be reading until killed. Naturally, the output can be
 redirected to a desirable location. This is preferred, because it is going
 to be quite long.
@@ -92,8 +100,9 @@ on the event type, but there is a set of words, common for all types.
 
 Here is the list of words, from left to right:
 
-- URB Tag. This is used to identify URBs is normally a kernel mode address
- of the URB structure in hexadecimal.
+- URB Tag. This is used to identify URBs, and is normally an in-kernel address
+  of the URB structure in hexadecimal, but can be a sequence number or any
+  other unique string, within reason.
 
 - Timestamp in microseconds, a decimal number. The timestamp's resolution
   depends on available clock, and so it can be much worse than a microsecond