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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 /kernel
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 'kernel')
-rw-r--r--kernel/power/Kconfig11
-rw-r--r--kernel/printk.c16
2 files changed, 14 insertions, 13 deletions
diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index 14b0e10dc95..8e186c67814 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -44,17 +44,6 @@ config PM_VERBOSE
---help---
This option enables verbose messages from the Power Management code.
-config DISABLE_CONSOLE_SUSPEND
- bool "Keep console(s) enabled during suspend/resume (DANGEROUS)"
- depends on PM_DEBUG && PM_SLEEP
- default n
- ---help---
- This option turns off the console suspend mechanism that prevents
- debug messages from reaching the console during the suspend/resume
- operations. This may be helpful when debugging device drivers'
- suspend/resume routines, but may itself lead to problems, for example
- if netconsole is used.
-
config PM_TRACE
bool "Suspend/resume event tracing"
depends on PM_DEBUG && X86 && PM_SLEEP && EXPERIMENTAL
diff --git a/kernel/printk.c b/kernel/printk.c
index 52493474f0a..a30fe33de39 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -862,7 +862,16 @@ int update_console_cmdline(char *name, int idx, char *name_new, int idx_new, cha
return -1;
}
-#ifndef CONFIG_DISABLE_CONSOLE_SUSPEND
+int console_suspend_enabled = 1;
+EXPORT_SYMBOL(console_suspend_enabled);
+
+static int __init console_suspend_disable(char *str)
+{
+ console_suspend_enabled = 0;
+ return 1;
+}
+__setup("no_console_suspend", console_suspend_disable);
+
/**
* suspend_console - suspend the console subsystem
*
@@ -870,6 +879,8 @@ int update_console_cmdline(char *name, int idx, char *name_new, int idx_new, cha
*/
void suspend_console(void)
{
+ if (!console_suspend_enabled)
+ return;
printk("Suspending console(s)\n");
acquire_console_sem();
console_suspended = 1;
@@ -877,10 +888,11 @@ void suspend_console(void)
void resume_console(void)
{
+ if (!console_suspend_enabled)
+ return;
console_suspended = 0;
release_console_sem();
}
-#endif /* CONFIG_DISABLE_CONSOLE_SUSPEND */
/**
* acquire_console_sem - lock the console system for exclusive use.