[PATCH] swsusp: documentation update

[PATCH] swsusp: documentation update

[Rafael J. Wysocki]

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Hi,

This patch updates the swsusp documentation to reflect the recent change
that prevented the kernel from setting to console loglevel to 10
unconditionally during suspend.  It also removes one obsolete paragraph.

Please review.

Greetings,
Rafael


Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

 Documentation/power/swsusp.txt |   15 ++++++++-------
 1 files changed, 8 insertions(+), 7 deletions(-)

Index: linux-2.6.16-rc1-mm5/Documentation/power/swsusp.txt
===================================================================
--- linux-2.6.16-rc1-mm5.orig/Documentation/power/swsusp.txt	2006-02-03 21:26:42.000000000 +0100
+++ linux-2.6.16-rc1-mm5/Documentation/power/swsusp.txt	2006-02-05 08:49:07.000000000 +0100
@@ -33,12 +33,13 @@ echo N > /sys/power/image_size
 
 before suspend (it is limited to 500 MB by default).
 
-Encrypted suspend image:
-------------------------
-If you want to store your suspend image encrypted with a temporary
-key to prevent data gathering after resume you must compile
-crypto and the aes algorithm into the kernel - modules won't work
-as they cannot be loaded at resume time.
+Kernel messages during suspend
+------------------------------
+If you want to see any kernel messages on the virtual terminal the kernel
+switches to during suspend, you have to set the kernel console loglevel to
+at least 4 (KERN_WARNING), for example by doing
+
+# echo 4 > /proc/sys/kernel/printk
 
 
 Article about goals and implementation of Software Suspend for Linux

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Re: [PATCH] swsusp: documentation update

[Rafael J. Wysocki]

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[Update]

On Sunday 05 February 2006 09:03, Rafael J. Wysocki wrote:
> Hi,
> 
> This patch updates the swsusp documentation to reflect the recent change
> that prevented the kernel from setting to console loglevel to 10
> unconditionally during suspend.  It also removes one obsolete paragraph.
> 
> Please review.
> 
> Greetings,
> Rafael
> 
> 
> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
> 
>  Documentation/power/swsusp.txt |   15 ++++++++-------
>  1 files changed, 8 insertions(+), 7 deletions(-)
> 
> Index: linux-2.6.16-rc1-mm5/Documentation/power/swsusp.txt
> ===================================================================
> --- linux-2.6.16-rc1-mm5.orig/Documentation/power/swsusp.txt	2006-02-03 21:26:42.000000000 +0100
> +++ linux-2.6.16-rc1-mm5/Documentation/power/swsusp.txt	2006-02-05 08:49:07.000000000 +0100
> @@ -33,12 +33,13 @@ echo N > /sys/power/image_size
>  
>  before suspend (it is limited to 500 MB by default).
>  
> -Encrypted suspend image:
> -------------------------
> -If you want to store your suspend image encrypted with a temporary
> -key to prevent data gathering after resume you must compile
> -crypto and the aes algorithm into the kernel - modules won't work
> -as they cannot be loaded at resume time.
> +Kernel messages during suspend
> +------------------------------
> +If you want to see any kernel messages on the virtual terminal the kernel

s/any kernel messages/any non-error kernel messages/

[Sorry.]

> +switches to during suspend, you have to set the kernel console loglevel to
> +at least 4 (KERN_WARNING), for example by doing
> +
> +# echo 4 > /proc/sys/kernel/printk

Rafael

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Re: [PATCH] swsusp: documentation update

[Pavel Machek]

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On Ne 05-02-06 09:03:48, Rafael J. Wysocki wrote:
> Hi,
> 
> This patch updates the swsusp documentation to reflect the recent change
> that prevented the kernel from setting to console loglevel to 10
> unconditionally during suspend.  It also removes one obsolete
> paragraph.

I'd say that kernel messages are common knowledge and do not deserve
to be *that* visible.

What about this? If you agree, I'll push it to akpm.

diff --git a/Documentation/power/swsusp.txt b/Documentation/power/swsusp.txt
index b28b7f0..96bbe61 100644
--- a/Documentation/power/swsusp.txt
+++ b/Documentation/power/swsusp.txt
@@ -27,19 +27,18 @@ echo shutdown > /sys/power/disk; echo di
 
 echo platform > /sys/power/disk; echo disk > /sys/power/state
 
+. If you have SATA disks, you'll need recent kernels with SATA suspend
+support. For suspend and resume to work, make sure your disk drivers
+are built into kernel -- not modules. [There's way to make
+suspend/resume with modular disk drivers, see FAQ, but you probably
+should not do that.]
+
 If you want to limit the suspend image size to N bytes, do
 
 echo N > /sys/power/image_size
 
 before suspend (it is limited to 500 MB by default).
 
-Encrypted suspend image:
-------------------------
-If you want to store your suspend image encrypted with a temporary
-key to prevent data gathering after resume you must compile
-crypto and the aes algorithm into the kernel - modules won't work
-as they cannot be loaded at resume time.
-
 
 Article about goals and implementation of Software Suspend for Linux
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -333,4 +332,19 @@ init=/bin/bash, then swapon and starting
 usually does the trick. Then it is good idea to try with latest
 vanilla kernel.
 
+Q: How can distributions ship a swsusp-supporting kernel with modular
+disk drivers (especially SATA)?
+
+A: Well, it can be done, load the drivers, then do echo into
+/sys/power/disk/resume file from initrd. Be sure not to mount
+anything, not even read-only mount, or you are going to lose your
+data.
+
+Q: How do I make suspend more verbose?
+
+A: If you want to see any non-error kernel messages on the virtual
+terminal the kernel switches to during suspend, you have to set the
+kernel console loglevel to at least 4 (KERN_WARNING), for example by
+doing
 
+	echo 4 > /proc/sys/kernel/printk



-- 
Thanks, Sharp!

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