releases/3.8.8/pm-reboot-call-syscore_shutdown-after-disable_nonboot_cpus.patch

   1 From 6f389a8f1dd22a24f3d9afc2812b30d639e94625 Mon Sep 17 00:00:00 2001
   2 From: Huacai Chen <chenhc@lemote.com>
   3 Date: Sun, 7 Apr 2013 02:14:14 +0000
   4 Subject: PM / reboot: call syscore_shutdown() after disable_nonboot_cpus()
   5
   6 From: Huacai Chen <chenhc@lemote.com>
   7
   8 commit 6f389a8f1dd22a24f3d9afc2812b30d639e94625 upstream.
   9
  10 As commit 40dc166c (PM / Core: Introduce struct syscore_ops for core
  11 subsystems PM) say, syscore_ops operations should be carried with one
  12 CPU on-line and interrupts disabled. However, after commit f96972f2d
  13 (kernel/sys.c: call disable_nonboot_cpus() in kernel_restart()),
  14 syscore_shutdown() is called before disable_nonboot_cpus(), so break
  15 the rules. We have a MIPS machine with a 8259A PIC, and there is an
  16 external timer (HPET) linked at 8259A. Since 8259A has been shutdown
  17 too early (by syscore_shutdown()), disable_nonboot_cpus() runs without
  18 timer interrupt, so it hangs and reboot fails. This patch call
  19 syscore_shutdown() a little later (after disable_nonboot_cpus()) to
  20 avoid reboot failure, this is the same way as poweroff does.
  21
  22 For consistency, add disable_nonboot_cpus() to kernel_halt().
  23
  24 Signed-off-by: Huacai Chen <chenhc@lemote.com>
  25 Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
  26 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  27
  28 ---
  29  kernel/sys.c |    3 ++-
  30  1 file changed, 2 insertions(+), 1 deletion(-)
  31
  32 --- a/kernel/sys.c
  33 +++ b/kernel/sys.c
  34 @@ -323,7 +323,6 @@ void kernel_restart_prepare(char *cmd)
  35         system_state = SYSTEM_RESTART;
  36         usermodehelper_disable();
  37         device_shutdown();
  38 -       syscore_shutdown();
  39  }
  40
  41  /**
  42 @@ -369,6 +368,7 @@ void kernel_restart(char *cmd)
  43  {
  44         kernel_restart_prepare(cmd);
  45         disable_nonboot_cpus();
  46 +       syscore_shutdown();
  47         if (!cmd)
  48                 printk(KERN_EMERG "Restarting system.\n");
  49         else
  50 @@ -394,6 +394,7 @@ static void kernel_shutdown_prepare(enum
  51  void kernel_halt(void)
  52  {
  53         kernel_shutdown_prepare(SYSTEM_HALT);
  54 +       disable_nonboot_cpus();
  55         syscore_shutdown();
  56         printk(KERN_EMERG "System halted.\n");
  57         kmsg_dump(KMSG_DUMP_HALT);