[RFC][PATCH -mm] swsusp userland interface: additional ioctl

[RFC][PATCH -mm] swsusp userland interface: additional ioctl

[Rafael J. Wysocki]

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Hi,

The appended patch provides an additional ioctl() for the swsusp userland
interface that will allow the suspending and/or resuming utilities to change
the kernel log level at the time of suspend/resume (or even set it to 0 if
they are going to use some frame buffer graphics etc.).

Comments welcome.

Greetings,
Rafael


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

 kernel/power/console.c |    5 +++--
 kernel/power/power.h   |    6 +++++-
 kernel/power/user.c    |    5 +++++
 3 files changed, 13 insertions(+), 3 deletions(-)

Index: linux-2.6.16-rc1-mm3/kernel/power/console.c
===================================================================
--- linux-2.6.16-rc1-mm3.orig/kernel/power/console.c	2006-01-15 12:42:27.000000000 +0100
+++ linux-2.6.16-rc1-mm3/kernel/power/console.c	2006-01-29 21:24:48.000000000 +0100
@@ -9,7 +9,8 @@
 #include <linux/console.h>
 #include "power.h"
 
-static int new_loglevel = 10;
+int suspend_loglevel = DEFAULT_SUSPEND_LOGLEVEL;
+
 static int orig_loglevel;
 #ifdef SUSPEND_CONSOLE
 static int orig_fgconsole, orig_kmsg;
@@ -18,7 +19,7 @@ static int orig_fgconsole, orig_kmsg;
 int pm_prepare_console(void)
 {
 	orig_loglevel = console_loglevel;
-	console_loglevel = new_loglevel;
+	console_loglevel = suspend_loglevel;
 
 #ifdef SUSPEND_CONSOLE
 	acquire_console_sem();
Index: linux-2.6.16-rc1-mm3/kernel/power/power.h
===================================================================
--- linux-2.6.16-rc1-mm3.orig/kernel/power/power.h	2006-01-25 21:21:13.000000000 +0100
+++ linux-2.6.16-rc1-mm3/kernel/power/power.h	2006-01-29 21:24:58.000000000 +0100
@@ -55,6 +55,9 @@ extern struct pbe *pagedir_nosave;
 extern unsigned long image_size;
 extern int in_suspend;
 extern dev_t swsusp_resume_device;
+extern int suspend_loglevel;
+
+#define DEFAULT_SUSPEND_LOGLEVEL	10
 
 extern asmlinkage int swsusp_arch_suspend(void);
 extern asmlinkage int swsusp_arch_resume(void);
@@ -88,7 +91,8 @@ int snapshot_image_loaded(struct snapsho
 #define SNAPSHOT_GET_SWAP_PAGE		_IOR(SNAPSHOT_IOC_MAGIC, 8, void *)
 #define SNAPSHOT_FREE_SWAP_PAGES	_IO(SNAPSHOT_IOC_MAGIC, 9)
 #define SNAPSHOT_SET_SWAP_FILE		_IOW(SNAPSHOT_IOC_MAGIC, 10, unsigned int)
-#define SNAPSHOT_IOC_MAXNR	10
+#define SNAPSHOT_SET_LOGLEVEL		_IOW(SNAPSHOT_IOC_MAGIC, 11, int)
+#define SNAPSHOT_IOC_MAXNR	11
 
 /**
  *	The bitmap is used for tracing allocated swap pages
Index: linux-2.6.16-rc1-mm3/kernel/power/user.c
===================================================================
--- linux-2.6.16-rc1-mm3.orig/kernel/power/user.c	2006-01-25 21:53:52.000000000 +0100
+++ linux-2.6.16-rc1-mm3/kernel/power/user.c	2006-01-29 21:24:48.000000000 +0100
@@ -78,6 +78,7 @@ static int snapshot_release(struct inode
 		enable_nonboot_cpus();
 		up(&pm_sem);
 	}
+	suspend_loglevel = DEFAULT_SUSPEND_LOGLEVEL;
 	atomic_inc(&device_available);
 	return 0;
 }
@@ -264,6 +265,10 @@ static int snapshot_ioctl(struct inode *
 		}
 		break;
 
+	case SNAPSHOT_SET_LOGLEVEL:
+		suspend_loglevel = arg <= 10 ? arg : DEFAULT_SUSPEND_LOGLEVEL;
+		break;
+
 	default:
 		error = -ENOTTY;
 

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Re: [RFC][PATCH -mm] swsusp userland interface: additional ioctl

[Pavel Machek]

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Hi!

> The appended patch provides an additional ioctl() for the swsusp userland
> interface that will allow the suspending and/or resuming utilities to change
> the kernel log level at the time of suspend/resume (or even set it to 0 if
> they are going to use some frame buffer graphics etc.).

klogd can already change loglevel... It should be possible to use that
to silence suspend, no?

									Pavel

-- 
Thanks, Sharp!

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Re: [RFC][PATCH -mm] swsusp userland interface: additional ioctl

[Rafael J. Wysocki]

Hi,

On Sunday 29 January 2006 22:57, Pavel Machek wrote:
> > The appended patch provides an additional ioctl() for the swsusp userland
> > interface that will allow the suspending and/or resuming utilities to change
> > the kernel log level at the time of suspend/resume (or even set it to 0 if
> > they are going to use some frame buffer graphics etc.).
> 
> klogd can already change loglevel... It should be possible to use that
> to silence suspend, no?

Well, no.  Currently the kernel changes the log level to 10 unconditionally
in pm_prepare_console() (that's the reason for the patch, BTW).

Rafael

Re: [RFC][PATCH -mm] swsusp userland interface: additional ioctl

[Pavel Machek]

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Hi!

> > > The appended patch provides an additional ioctl() for the swsusp userland
> > > interface that will allow the suspending and/or resuming utilities to change
> > > the kernel log level at the time of suspend/resume (or even set it to 0 if
> > > they are going to use some frame buffer graphics etc.).
> > 
> > klogd can already change loglevel... It should be possible to use that
> > to silence suspend, no?
> 
> Well, no.  Currently the kernel changes the log level to 10 unconditionally
> in pm_prepare_console() (that's the reason for the patch, BTW).

Can we just kill that log-level setting? It may have been useful in
the past, but I do not think it has right to live any more.
								Pavel
-- 
Thanks, Sharp!

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Re: Re: [RFC][PATCH -mm] swsusp userland interface: additional ioctl

[Greg KH]

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On Mon, Jan 30, 2006 at 12:06:47AM +0100, Pavel Machek wrote:
> Hi!
> 
> > > > The appended patch provides an additional ioctl() for the swsusp userland
> > > > interface that will allow the suspending and/or resuming utilities to change
> > > > the kernel log level at the time of suspend/resume (or even set it to 0 if
> > > > they are going to use some frame buffer graphics etc.).
> > > 
> > > klogd can already change loglevel... It should be possible to use that
> > > to silence suspend, no?
> > 
> > Well, no.  Currently the kernel changes the log level to 10 unconditionally
> > in pm_prepare_console() (that's the reason for the patch, BTW).
> 
> Can we just kill that log-level setting? It may have been useful in
> the past, but I do not think it has right to live any more.

Yes, change that, don't create another interface to the kernel where
there is already one.

thanks,

greg k-h

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Re: [RFC][PATCH -mm] swsusp userland interface: additional ioctl

[Rafael J. Wysocki]

Hi,

On Monday 30 January 2006 00:06, Pavel Machek wrote:
> > > > The appended patch provides an additional ioctl() for the swsusp userland
> > > > interface that will allow the suspending and/or resuming utilities to change
> > > > the kernel log level at the time of suspend/resume (or even set it to 0 if
> > > > they are going to use some frame buffer graphics etc.).
> > > 
> > > klogd can already change loglevel... It should be possible to use that
> > > to silence suspend, no?
> > 
> > Well, no.  Currently the kernel changes the log level to 10 unconditionally
> > in pm_prepare_console() (that's the reason for the patch, BTW).
> 
> Can we just kill that log-level setting? It may have been useful in
> the past, but I do not think it has right to live any more.

Sure, we can:

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

 kernel/power/console.c |   12 +-----------
 kernel/power/power.h   |    5 +++++
 2 files changed, 6 insertions(+), 11 deletions(-)

Index: linux-2.6.16-rc1-mm4/kernel/power/console.c
===================================================================
--- linux-2.6.16-rc1-mm4.orig/kernel/power/console.c	2006-01-30 21:17:53.000000000 +0100
+++ linux-2.6.16-rc1-mm4/kernel/power/console.c	2006-01-30 21:32:24.000000000 +0100
@@ -9,18 +9,11 @@
 #include <linux/console.h>
 #include "power.h"
 
-static int new_loglevel = 10;
-static int orig_loglevel;
 #ifdef SUSPEND_CONSOLE
 static int orig_fgconsole, orig_kmsg;
-#endif
 
 int pm_prepare_console(void)
 {
-	orig_loglevel = console_loglevel;
-	console_loglevel = new_loglevel;
-
-#ifdef SUSPEND_CONSOLE
 	acquire_console_sem();
 
 	orig_fgconsole = fg_console;
@@ -41,18 +34,15 @@ int pm_prepare_console(void)
 	}
 	orig_kmsg = kmsg_redirect;
 	kmsg_redirect = SUSPEND_CONSOLE;
-#endif
 	return 0;
 }
 
 void pm_restore_console(void)
 {
-	console_loglevel = orig_loglevel;
-#ifdef SUSPEND_CONSOLE
 	acquire_console_sem();
 	set_console(orig_fgconsole);
 	release_console_sem();
 	kmsg_redirect = orig_kmsg;
-#endif
 	return;
 }
+#endif
Index: linux-2.6.16-rc1-mm4/kernel/power/power.h
===================================================================
--- linux-2.6.16-rc1-mm4.orig/kernel/power/power.h	2006-01-30 21:19:43.000000000 +0100
+++ linux-2.6.16-rc1-mm4/kernel/power/power.h	2006-01-30 21:33:19.000000000 +0100
@@ -43,8 +43,13 @@ static struct subsys_attribute _name##_a
 
 extern struct subsystem power_subsys;
 
+#ifdef SUSPEND_CONSOLE
 extern int pm_prepare_console(void);
 extern void pm_restore_console(void);
+#else
+static int pm_prepare_console(void) { return 0; }
+static void pm_restore_console(void) {}
+#endif
 
 /* References to section boundaries */
 extern const void __nosave_begin, __nosave_end;

Re: [RFC][PATCH -mm] swsusp userland interface: additional ioctl

[Pavel Machek]

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Hi!

> > > > > The appended patch provides an additional ioctl() for the swsusp userland
> > > > > interface that will allow the suspending and/or resuming utilities to change
> > > > > the kernel log level at the time of suspend/resume (or even set it to 0 if
> > > > > they are going to use some frame buffer graphics etc.).
> > > > 
> > > > klogd can already change loglevel... It should be possible to use that
> > > > to silence suspend, no?
> > > 
> > > Well, no.  Currently the kernel changes the log level to 10 unconditionally
> > > in pm_prepare_console() (that's the reason for the patch, BTW).
> > 
> > Can we just kill that log-level setting? It may have been useful in
> > the past, but I do not think it has right to live any more.
> 
> Sure, we can:
> 
> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

ACK and thanks. Patches that remve code are always good.

							Pavel
-- 
Thanks, Sharp!

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