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author | Mauro Carvalho Chehab <mchehab@s-opensource.com> | 2017-04-17 02:51:06 +0200 |
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committer | Jonathan Corbet <corbet@lwn.net> | 2017-04-20 23:30:33 +0200 |
commit | 8a6a285d61fd0d602859c945892927ef87d26895 (patch) | |
tree | 3bf16c7b7f2d404a1f9a482492a1f5175b40860e /Documentation/usb/proc_usb_info.txt | |
parent | arm: Documentation: update a path name (diff) | |
download | linux-8a6a285d61fd0d602859c945892927ef87d26895.tar.xz linux-8a6a285d61fd0d602859c945892927ef87d26895.zip |
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.txt | 20 |
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, |