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-rw-r--r--Documentation/usb/proc_usb_info.txt34
1 files changed, 22 insertions, 12 deletions
diff --git a/Documentation/usb/proc_usb_info.txt b/Documentation/usb/proc_usb_info.txt
index fafcd472326..afe596d5f20 100644
--- a/Documentation/usb/proc_usb_info.txt
+++ b/Documentation/usb/proc_usb_info.txt
@@ -1,12 +1,17 @@
/proc/bus/usb filesystem output
===============================
-(version 2003.05.30)
+(version 2010.09.13)
The usbfs filesystem for USB devices is traditionally mounted at
/proc/bus/usb. It provides the /proc/bus/usb/devices file, as well as
the /proc/bus/usb/BBB/DDD files.
+In many modern systems the usbfs filsystem isn't used at all. Instead
+USB device nodes are created under /dev/usb/ or someplace similar. The
+"devices" file is available in debugfs, typically as
+/sys/kernel/debug/usb/devices.
+
**NOTE**: If /proc/bus/usb appears empty, and a host controller
driver has been linked, then you need to mount the
@@ -106,8 +111,8 @@ Legend:
Topology info:
-T: Bus=dd Lev=dd Prnt=dd Port=dd Cnt=dd Dev#=ddd Spd=ddd MxCh=dd
-| | | | | | | | |__MaxChildren
+T: Bus=dd Lev=dd Prnt=dd Port=dd Cnt=dd Dev#=ddd Spd=dddd MxCh=dd
+| | | | | | | | |__MaxChildren
| | | | | | | |__Device Speed in Mbps
| | | | | | |__DeviceNumber
| | | | | |__Count of devices at this level
@@ -120,8 +125,13 @@ T: Bus=dd Lev=dd Prnt=dd Port=dd Cnt=dd Dev#=ddd Spd=ddd MxCh=dd
Speed may be:
1.5 Mbit/s for low speed USB
12 Mbit/s for full speed USB
- 480 Mbit/s for high speed USB (added for USB 2.0)
+ 480 Mbit/s for high speed USB (added for USB 2.0);
+ also used for Wireless USB, which has no fixed speed
+ 5000 Mbit/s for SuperSpeed USB (added for USB 3.0)
+ For reasons lost in the mists of time, the Port number is always
+ too low by 1. For example, a device plugged into port 4 will
+ show up with "Port=03".
Bandwidth info:
B: Alloc=ddd/ddd us (xx%), #Int=ddd, #Iso=ddd
@@ -291,7 +301,7 @@ Here's an example, from a system which has a UHCI root hub,
an external hub connected to the root hub, and a mouse and
a serial converter connected to the external hub.
-T: Bus=00 Lev=00 Prnt=00 Port=00 Cnt=00 Dev#= 1 Spd=12 MxCh= 2
+T: Bus=00 Lev=00 Prnt=00 Port=00 Cnt=00 Dev#= 1 Spd=12 MxCh= 2
B: Alloc= 28/900 us ( 3%), #Int= 2, #Iso= 0
D: Ver= 1.00 Cls=09(hub ) Sub=00 Prot=00 MxPS= 8 #Cfgs= 1
P: Vendor=0000 ProdID=0000 Rev= 0.00
@@ -301,21 +311,21 @@ C:* #Ifs= 1 Cfg#= 1 Atr=40 MxPwr= 0mA
I: If#= 0 Alt= 0 #EPs= 1 Cls=09(hub ) Sub=00 Prot=00 Driver=hub
E: Ad=81(I) Atr=03(Int.) MxPS= 8 Ivl=255ms
-T: Bus=00 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#= 2 Spd=12 MxCh= 4
+T: Bus=00 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#= 2 Spd=12 MxCh= 4
D: Ver= 1.00 Cls=09(hub ) Sub=00 Prot=00 MxPS= 8 #Cfgs= 1
P: Vendor=0451 ProdID=1446 Rev= 1.00
C:* #Ifs= 1 Cfg#= 1 Atr=e0 MxPwr=100mA
I: If#= 0 Alt= 0 #EPs= 1 Cls=09(hub ) Sub=00 Prot=00 Driver=hub
E: Ad=81(I) Atr=03(Int.) MxPS= 1 Ivl=255ms
-T: Bus=00 Lev=02 Prnt=02 Port=00 Cnt=01 Dev#= 3 Spd=1.5 MxCh= 0
+T: Bus=00 Lev=02 Prnt=02 Port=00 Cnt=01 Dev#= 3 Spd=1.5 MxCh= 0
D: Ver= 1.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS= 8 #Cfgs= 1
P: Vendor=04b4 ProdID=0001 Rev= 0.00
C:* #Ifs= 1 Cfg#= 1 Atr=80 MxPwr=100mA
I: If#= 0 Alt= 0 #EPs= 1 Cls=03(HID ) Sub=01 Prot=02 Driver=mouse
E: Ad=81(I) Atr=03(Int.) MxPS= 3 Ivl= 10ms
-T: Bus=00 Lev=02 Prnt=02 Port=02 Cnt=02 Dev#= 4 Spd=12 MxCh= 0
+T: Bus=00 Lev=02 Prnt=02 Port=02 Cnt=02 Dev#= 4 Spd=12 MxCh= 0
D: Ver= 1.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS= 8 #Cfgs= 1
P: Vendor=0565 ProdID=0001 Rev= 1.08
S: Manufacturer=Peracom Networks, Inc.
@@ -330,12 +340,12 @@ E: Ad=82(I) Atr=03(Int.) MxPS= 8 Ivl= 8ms
Selecting only the "T:" and "I:" lines from this (for example, by using
"procusb ti"), we have:
-T: Bus=00 Lev=00 Prnt=00 Port=00 Cnt=00 Dev#= 1 Spd=12 MxCh= 2
-T: Bus=00 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#= 2 Spd=12 MxCh= 4
+T: Bus=00 Lev=00 Prnt=00 Port=00 Cnt=00 Dev#= 1 Spd=12 MxCh= 2
+T: Bus=00 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#= 2 Spd=12 MxCh= 4
I: If#= 0 Alt= 0 #EPs= 1 Cls=09(hub ) Sub=00 Prot=00 Driver=hub
-T: Bus=00 Lev=02 Prnt=02 Port=00 Cnt=01 Dev#= 3 Spd=1.5 MxCh= 0
+T: Bus=00 Lev=02 Prnt=02 Port=00 Cnt=01 Dev#= 3 Spd=1.5 MxCh= 0
I: If#= 0 Alt= 0 #EPs= 1 Cls=03(HID ) Sub=01 Prot=02 Driver=mouse
-T: Bus=00 Lev=02 Prnt=02 Port=02 Cnt=02 Dev#= 4 Spd=12 MxCh= 0
+T: Bus=00 Lev=02 Prnt=02 Port=02 Cnt=02 Dev#= 4 Spd=12 MxCh= 0
I: If#= 0 Alt= 0 #EPs= 3 Cls=00(>ifc ) Sub=00 Prot=00 Driver=serial