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authorAndres Salomon <dilinger@debian.org>2007-10-18 03:04:50 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-10-18 14:37:19 -0700
commit8f4ce8c32f2dc2bc2411cafe39976fc5c0adfabf (patch)
tree04f9009812e13f97b3eaae6385a0bb49cc2312b1 /Documentation
parent438e2ce68dfd4af4cfcec2f873564fb921db4bb5 (diff)
serial: turn serial console suspend a boot rather than compile time option
Currently, there's a CONFIG_DISABLE_CONSOLE_SUSPEND that allows one to stop the serial console from being suspended when the rest of the machine goes to sleep. This is incredibly useful for debugging power management-related things; however, having it as a compile-time option has proved to be incredibly inconvenient for us (OLPC). There are plenty of times that we want serial console to not suspend, but for the most part we'd like serial console to be suspended. This drops CONFIG_DISABLE_CONSOLE_SUSPEND, and replaces it with a kernel boot parameter (no_console_suspend). By default, the serial console will be suspended along with the rest of the system; by passing 'no_console_suspend' to the kernel during boot, serial console will remain alive during suspend. For now, this is pretty serial console specific; further fixes could be applied to make this work for things like netconsole. Signed-off-by: Andres Salomon <dilinger@debian.org> Acked-by: "Rafael J. Wysocki" <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Cc: Nigel Cunningham <nigel@suspend2.net> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/kernel-parameters.txt10
-rw-r--r--Documentation/power/basic-pm-debugging.txt4
2 files changed, 12 insertions, 2 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 98cf90f2631..189df0bcab9 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -479,6 +479,16 @@ and is between 256 and 4096 characters. It is defined in the file
UART at the specified I/O port or MMIO address.
The options are the same as for ttyS, above.
+ no_console_suspend
+ [HW] Never suspend the console
+ Disable suspending of consoles during suspend and
+ hibernate operations. Once disabled, debugging
+ messages can reach various consoles while the rest
+ of the system is being put to sleep (ie, while
+ debugging driver suspend/resume hooks). This may
+ not work reliably with all consoles, but is known
+ to work with serial and VGA consoles.
+
cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
Format:
<first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
diff --git a/Documentation/power/basic-pm-debugging.txt b/Documentation/power/basic-pm-debugging.txt
index 1a85e2b964d..57aef2f6e0d 100644
--- a/Documentation/power/basic-pm-debugging.txt
+++ b/Documentation/power/basic-pm-debugging.txt
@@ -78,8 +78,8 @@ c) Advanced debugging
In case the STD does not work on your system even in the minimal configuration
and compiling more drivers as modules is not practical or some modules cannot
be unloaded, you can use one of the more advanced debugging techniques to find
-the problem. First, if there is a serial port in your box, you can set the
-CONFIG_DISABLE_CONSOLE_SUSPEND kernel configuration option and try to log kernel
+the problem. First, if there is a serial port in your box, you can boot the
+kernel with the 'no_console_suspend' parameter and try to log kernel
messages using the serial console. This may provide you with some information
about the reasons of the suspend (resume) failure. Alternatively, it may be
possible to use a FireWire port for debugging with firescope