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authorMauro Carvalho Chehab <mchehab@s-opensource.com>2017-04-17 02:51:06 +0200
committerJonathan Corbet <corbet@lwn.net>2017-04-20 23:30:33 +0200
commit8a6a285d61fd0d602859c945892927ef87d26895 (patch)
tree3bf16c7b7f2d404a1f9a482492a1f5175b40860e /Documentation/usb/proc_usb_info.txt
parentarm: Documentation: update a path name (diff)
downloadlinux-8a6a285d61fd0d602859c945892927ef87d26895.tar.xz
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docs-rst: usb: update old usbfs-related documentation
There's no usbfs anymore. The old features are now either exported to /dev/bus/usb or via debugfs. Update documentation accordingly, pointing to the new places where the character devices and usb/devices are now placed. Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Diffstat (limited to 'Documentation/usb/proc_usb_info.txt')
-rw-r--r--Documentation/usb/proc_usb_info.txt20
1 files changed, 10 insertions, 10 deletions
diff --git a/Documentation/usb/proc_usb_info.txt b/Documentation/usb/proc_usb_info.txt
index 98be91982677..06d7960e9ae6 100644
--- a/Documentation/usb/proc_usb_info.txt
+++ b/Documentation/usb/proc_usb_info.txt
@@ -4,7 +4,7 @@
The usbfs filesystem for USB devices is traditionally mounted at
-/proc/bus/usb. It provides the /proc/bus/usb/devices file, as well as
+/proc/bus/usb. It provides the /sys/kernel/debug/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
@@ -24,7 +24,7 @@ USB device nodes are created under /dev/usb/ or someplace similar. The
none /proc/bus/usb usbfs defaults 0 0
to /etc/fstab. This will mount usbfs at each reboot.
- You can then issue `cat /proc/bus/usb/devices` to extract
+ You can then issue `cat /sys/kernel/debug/usb/devices` to extract
USB device information, and user mode drivers can use usbfs
to interact with USB devices.
@@ -60,7 +60,7 @@ 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.
+in text form by the /sys/kernel/debug/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,
@@ -79,9 +79,9 @@ usbfs mount options such as "devmode=0666" may be helpful.
-THE /proc/bus/usb/devices FILE:
+THE /sys/kernel/debug/usb/devices FILE:
-------------------------------
-In /proc/bus/usb/devices, each device's output has multiple
+In /sys/kernel/debug/usb/devices, each device's output has multiple
lines of ASCII output.
I made it ASCII instead of binary on purpose, so that someone
can obtain some useful data from it without the use of an
@@ -104,7 +104,7 @@ E = Endpoint descriptor info.
=======================================================================
-/proc/bus/usb/devices output format:
+/sys/kernel/debug/usb/devices output format:
Legend:
d = decimal number (may have leading spaces or 0's)
@@ -277,16 +277,16 @@ E: Ad=xx(s) Atr=xx(ssss) MxPS=dddd Ivl=dddss
If a user or script is interested only in Topology info, for
-example, use something like "grep ^T: /proc/bus/usb/devices"
+example, use something like "grep ^T: /sys/kernel/debug/usb/devices"
for only the Topology lines. A command like
-"grep -i ^[tdp]: /proc/bus/usb/devices" can be used to list
+"grep -i ^[tdp]: /sys/kernel/debug/usb/devices" can be used to list
only the lines that begin with the characters in square brackets,
where the valid characters are TDPCIE. With a slightly more able
script, it can display any selected lines (for example, only T, D,
and P lines) and change their output format. (The "procusb"
Perl script is the beginning of this idea. It will list only
selected lines [selected from TBDPSCIE] or "All" lines from
-/proc/bus/usb/devices.)
+/sys/kernel/debug/usb/devices.)
The Topology lines can be used to generate a graphic/pictorial
of the USB devices on a system's root hub. (See more below
@@ -297,7 +297,7 @@ 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.
-For example, "grep ^C: /proc/bus/usb/devices".
+For example, "grep ^C: /sys/kernel/debug/usb/devices".
Here's an example, from a system which has a UHCI root hub,