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authorDr. Werner Fink <werner@suse.de>2010-09-22 12:45:40 +0200
committerGreg Kroah-Hartman <gregkh@suse.de>2010-10-22 10:20:05 -0700
commitf4a3e0bceb57466c31757f25e4e0ed108d1299ec (patch)
treec08eda0100e97ebd1fe4ab90b5d8eb142e505673 /Documentation
parenta9e2e06015201c32c43d3615c9bf5e0d4efb4302 (diff)
tty: Add a new file /proc/tty/consoles
Add a new file /proc/tty/consoles to be able to determine the registered system console lines. If the reading process holds /dev/console open at the regular standard input stream the active device will be marked by an asterisk. Show possible operations and also decode the used flags of the listed console lines. Signed-off-by: Werner Fink <werner@suse.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/filesystems/proc.txt32
1 files changed, 32 insertions, 0 deletions
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index a6aca874088..98223a67694 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -1075,6 +1075,7 @@ Table 1-11: Files in /proc/tty
drivers list of drivers and their usage
ldiscs registered line disciplines
driver/serial usage statistic and status of single tty lines
+ consoles registered system console lines
..............................................................................
To see which tty's are currently in use, you can simply look into the file
@@ -1093,6 +1094,37 @@ To see which tty's are currently in use, you can simply look into the file
/dev/tty /dev/tty 5 0 system:/dev/tty
unknown /dev/tty 4 1-63 console
+To see which character device lines are currently used for the system console
+/dev/console, you may simply look into the file /proc/tty/consoles:
+
+ > cat /proc/tty/consoles
+ tty0 -WU (ECp) 4:7
+ ttyS0 -W- (Ep) 4:64
+
+The columns are:
+
+ device name of the device
+ operations R = can do read operations
+ W = can do write operations
+ U = can do unblank
+ flags E = it is enabled
+ C = it is prefered console
+ B = it is primary boot console
+ p = it is used for printk buffer
+ b = it is not a TTY but a Braille device
+ a = it is safe to use when cpu is offline
+ * = it is standard input of the reading process
+ major:minor major and minor number of the device separated by a colon
+
+If the reading process holds /dev/console open at the regular standard input
+stream the active device will be marked by an asterisk:
+
+ > cat /proc/tty/consoles < /dev/console
+ tty0 -WU (ECp*) 4:7
+ ttyS0 -W- (Ep) 4:64
+ > tty
+ /dev/pts/3
+
1.8 Miscellaneous kernel statistics in /proc/stat
-------------------------------------------------