diff options
Diffstat (limited to 'Documentation/usb/proc_usb_info.txt')
| -rw-r--r-- | Documentation/usb/proc_usb_info.txt | 79 |
1 files changed, 49 insertions, 30 deletions
diff --git a/Documentation/usb/proc_usb_info.txt b/Documentation/usb/proc_usb_info.txt index 729c72d34c8..98be9198267 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 filesystem 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 @@ -20,7 +25,7 @@ the /proc/bus/usb/BBB/DDD files. to /etc/fstab. This will mount usbfs at each reboot. You can then issue `cat /proc/bus/usb/devices` to extract - USB device information, and user mode drivers can use usbfs + USB device information, and user mode drivers can use usbfs to interact with USB devices. There are a number of mount options supported by usbfs. @@ -32,7 +37,7 @@ the /proc/bus/usb/BBB/DDD files. still see references to the older "usbdevfs" name. For more information on mounting the usbfs file system, see the -"USB Device Filesystem" section of the USB Guide. The latest copy +"USB Device Filesystem" section of the USB Guide. The latest copy of the USB Guide can be found at http://www.linux-usb.org/ @@ -49,8 +54,13 @@ it and 002/048 sometime later. These files can be read as binary data. The binary data consists of first the device descriptor, then the descriptors for each -configuration of the device. That information is also shown in -text form by the /proc/bus/usb/devices file, described later. +configuration of the device. Multi-byte fields in the device descriptor +are converted to host endianness by the kernel. The configuration +descriptors are in bus endian format! The configuration descriptor +are wTotalLength bytes apart. If a device returns less configuration +descriptor data than indicated by wTotalLength there will be a hole in +the file for the missing bytes. This information is also shown +in text form by the /proc/bus/usb/devices file, described later. These files may also be used to write user-level drivers for the USB devices. You would open the /proc/bus/usb/BBB/DDD file read/write, @@ -59,7 +69,7 @@ bind to an interface (or perhaps several) using an ioctl call. You would issue more ioctls to the device to communicate to it using control, bulk, or other kinds of USB transfers. The IOCTLs are listed in the <linux/usbdevice_fs.h> file, and at this writing the -source code (linux/drivers/usb/devio.c) is the primary reference +source code (linux/drivers/usb/core/devio.c) is the primary reference for how to access devices through those files. Note that since by default these BBB/DDD files are writable only by @@ -104,8 +114,8 @@ 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 @@ -118,8 +128,13 @@ 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 @@ -133,7 +148,7 @@ B: Alloc=ddd/ddd us (xx%), #Int=ddd, #Iso=ddd are the only transfers that reserve bandwidth. Control and bulk transfers use all other bandwidth, including reserved bandwidth that is not used for transfers (such as for short packets). - + The percentage is how much of the "reserved" bandwidth is scheduled by those transfers. For a low or full speed bus (loosely, "USB 1.1"), 90% of the bus bandwidth is reserved. For a high speed bus (loosely, @@ -197,7 +212,7 @@ C:* #Ifs=dd Cfg#=dd Atr=xx MPwr=dddmA | | |__NumberOfInterfaces | |__ "*" indicates the active configuration (others are " ") |__Config info tag - + USB devices may have multiple configurations, each of which act rather differently. For example, a bus-powered configuration might be much less capable than one that is self-powered. Only @@ -213,22 +228,23 @@ C:* #Ifs=dd Cfg#=dd Atr=xx MPwr=dddmA Interface descriptor info (can be multiple per Config): -I: If#=dd Alt=dd #EPs=dd Cls=xx(sssss) Sub=xx Prot=xx Driver=ssss -| | | | | | | |__Driver name -| | | | | | | or "(none)" -| | | | | | |__InterfaceProtocol -| | | | | |__InterfaceSubClass -| | | | |__InterfaceClass -| | | |__NumberOfEndpoints -| | |__AlternateSettingNumber -| |__InterfaceNumber +I:* If#=dd Alt=dd #EPs=dd Cls=xx(sssss) Sub=xx Prot=xx Driver=ssss +| | | | | | | | |__Driver name +| | | | | | | | or "(none)" +| | | | | | | |__InterfaceProtocol +| | | | | | |__InterfaceSubClass +| | | | | |__InterfaceClass +| | | | |__NumberOfEndpoints +| | | |__AlternateSettingNumber +| | |__InterfaceNumber +| |__ "*" indicates the active altsetting (others are " ") |__Interface info tag A given interface may have one or more "alternate" settings. For example, default settings may not use more than a small amount of periodic bandwidth. To use significant fractions of bus bandwidth, drivers must select a non-default altsetting. - + Only one setting for an interface may be active at a time, and only one driver may bind to an interface at a time. Most devices have only one alternate setting per interface. @@ -277,7 +293,7 @@ of the USB devices on a system's root hub. (See more below on how to do this.) The Interface lines can be used to determine what driver is -being used for each device. +being used for each device, and which altsetting it activated. The Configuration lines could be used to list maximum power (in milliamps) that a system's USB devices are using. @@ -288,7 +304,7 @@ 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 @@ -297,19 +313,22 @@ S: SerialNumber=dce0 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. @@ -324,12 +343,12 @@ 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 |