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authorIan Abbott <abbotti@mev.co.uk>2019-09-11 19:39:41 +0300
committerJonathan Corbet <corbet@lwn.net>2019-09-14 10:51:46 +0300
commitd62e8055a596b3d3f11c1643ba18a9cbf093a0b9 (patch)
treed3dd1b921ebaf97dab0e8fbc3f6f4f29877cb2b7 /Documentation
parente62be10350ebcbfe99bd3fc0e15a0e21b1352fde (diff)
downloadlinux-d62e8055a596b3d3f11c1643ba18a9cbf093a0b9.tar.xz
devices.txt: improve entry for comedi (char major 98)
Describe how the comedi minor device numbers are split across comedi devices and comedi subdevices. Replace the current, long dead URL with an official URL for the Comedi project. Signed-off-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/admin-guide/devices.txt11
1 files changed, 10 insertions, 1 deletions
diff --git a/Documentation/admin-guide/devices.txt b/Documentation/admin-guide/devices.txt
index e56e00655153..1c5d2281efc9 100644
--- a/Documentation/admin-guide/devices.txt
+++ b/Documentation/admin-guide/devices.txt
@@ -1647,8 +1647,17 @@
0 = /dev/comedi0 First comedi device
1 = /dev/comedi1 Second comedi device
...
+ 47 = /dev/comedi47 48th comedi device
- See http://stm.lbl.gov/comedi.
+ Minors 48 to 255 are reserved for comedi subdevices with
+ pathnames of the form "/dev/comediX_subdY", where "X" is the
+ minor number of the associated comedi device and "Y" is the
+ subdevice number. These subdevice minors are assigned
+ dynamically, so there is no fixed mapping from subdevice
+ pathnames to minor numbers.
+
+ See http://www.comedi.org/ for information about the Comedi
+ project.
98 block User-mode virtual block device
0 = /dev/ubda First user-mode block device