Re: [PATCH 0/23] reboot-fixes

From: Andrew Morton
Date: Wed Jul 27 2005 - 12:46:03 EST


ebiederm@xxxxxxxxxxxx (Eric W. Biederman) wrote:
>
> Andrew Morton <akpm@xxxxxxxx> writes:
>
> > My fairly ordinary x86 test box gets stuck during reboot on the
> > wait_for_completion() in ide_do_drive_cmd():
>
> Hmm. The only thing I can think of is someone started adding calls
> to device_suspend() before device_shutdown(). Not understanding
> where it was a good idea I made certain the calls were in there
> consistently.
>
> Andrew can you remove the call to device_suspend from kernel_restart
> and see if this still happens?

yup, that fixes it.

--- devel/kernel/sys.c~a 2005-07-27 10:36:06.000000000 -0700
+++ devel-akpm/kernel/sys.c 2005-07-27 10:36:26.000000000 -0700
@@ -371,7 +371,6 @@ void kernel_restart(char *cmd)
{
notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
system_state = SYSTEM_RESTART;
- device_suspend(PMSG_FREEZE);
device_shutdown();
if (!cmd) {
printk(KERN_EMERG "Restarting system.\n");
_


Presumably it unfixes Pavel's patch?


From: Pavel Machek <pavel@xxxxxx>

Without this patch, Linux provokes emergency disk shutdowns and
similar nastiness. It was in SuSE kernels for some time, IIRC.

Signed-off-by: Pavel Machek <pavel@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---

include/linux/pm.h | 33 +++++++++++++++++++++------------
kernel/sys.c | 3 +++
2 files changed, 24 insertions(+), 12 deletions(-)

diff -puN kernel/sys.c~properly-stop-devices-before-poweroff kernel/sys.c
--- 25/kernel/sys.c~properly-stop-devices-before-poweroff 2005-06-25 14:47:00.000000000 -0700
+++ 25-akpm/kernel/sys.c 2005-06-25 14:50:53.000000000 -0700
@@ -405,6 +405,7 @@ asmlinkage long sys_reboot(int magic1, i
case LINUX_REBOOT_CMD_HALT:
notifier_call_chain(&reboot_notifier_list, SYS_HALT, NULL);
system_state = SYSTEM_HALT;
+ device_suspend(PMSG_SUSPEND);
device_shutdown();
printk(KERN_EMERG "System halted.\n");
machine_halt();
@@ -415,6 +416,7 @@ asmlinkage long sys_reboot(int magic1, i
case LINUX_REBOOT_CMD_POWER_OFF:
notifier_call_chain(&reboot_notifier_list, SYS_POWER_OFF, NULL);
system_state = SYSTEM_POWER_OFF;
+ device_suspend(PMSG_SUSPEND);
device_shutdown();
printk(KERN_EMERG "Power down.\n");
machine_power_off();
@@ -431,6 +433,7 @@ asmlinkage long sys_reboot(int magic1, i

notifier_call_chain(&reboot_notifier_list, SYS_RESTART, buffer);
system_state = SYSTEM_RESTART;
+ device_suspend(PMSG_FREEZE);
device_shutdown();
printk(KERN_EMERG "Restarting system with command '%s'.\n", buffer);
machine_restart(buffer);
diff -puN include/linux/pm.h~properly-stop-devices-before-poweroff include/linux/pm.h
--- 25/include/linux/pm.h~properly-stop-devices-before-poweroff 2005-06-25 14:47:00.000000000 -0700
+++ 25-akpm/include/linux/pm.h 2005-06-25 14:47:00.000000000 -0700
@@ -103,7 +103,8 @@ extern int pm_active;
/*
* Register a device with power management
*/
-struct pm_dev __deprecated *pm_register(pm_dev_t type, unsigned long id, pm_callback callback);
+struct pm_dev __deprecated *
+pm_register(pm_dev_t type, unsigned long id, pm_callback callback);

/*
* Unregister a device with power management
@@ -190,17 +191,18 @@ typedef u32 __bitwise pm_message_t;
/*
* There are 4 important states driver can be in:
* ON -- driver is working
- * FREEZE -- stop operations and apply whatever policy is applicable to a suspended driver
- * of that class, freeze queues for block like IDE does, drop packets for
- * ethernet, etc... stop DMA engine too etc... so a consistent image can be
- * saved; but do not power any hardware down.
- * SUSPEND - like FREEZE, but hardware is doing as much powersaving as possible. Roughly
- * pci D3.
+ * FREEZE -- stop operations and apply whatever policy is applicable to a
+ * suspended driver of that class, freeze queues for block like IDE
+ * does, drop packets for ethernet, etc... stop DMA engine too etc...
+ * so a consistent image can be saved; but do not power any hardware
+ * down.
+ * SUSPEND - like FREEZE, but hardware is doing as much powersaving as
+ * possible. Roughly pci D3.
*
- * Unfortunately, current drivers only recognize numeric values 0 (ON) and 3 (SUSPEND).
- * We'll need to fix the drivers. So yes, putting 3 to all diferent defines is intentional,
- * and will go away as soon as drivers are fixed. Also note that typedef is neccessary,
- * we'll probably want to switch to
+ * Unfortunately, current drivers only recognize numeric values 0 (ON) and 3
+ * (SUSPEND). We'll need to fix the drivers. So yes, putting 3 to all different
+ * defines is intentional, and will go away as soon as drivers are fixed. Also
+ * note that typedef is neccessary, we'll probably want to switch to
* typedef struct pm_message_t { int event; int flags; } pm_message_t
* or something similar soon.
*/
@@ -222,11 +224,18 @@ struct dev_pm_info {

extern void device_pm_set_parent(struct device * dev, struct device * parent);

-extern int device_suspend(pm_message_t state);
extern int device_power_down(pm_message_t state);
extern void device_power_up(void);
extern void device_resume(void);

+#ifdef CONFIG_PM
+extern int device_suspend(pm_message_t state);
+#else
+static inline int device_suspend(pm_message_t state)
+{
+ return 0;
+}
+#endif

#endif /* __KERNEL__ */

_

-
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