Function clockevents_switch_state() will check whether it has already
switched to specified state, do nothing if it has.

In function tick_shutdown(), it will set detached state at first and
call clockevents_switch_state() in clockevents_exchange_device(). The
function clockevents_switch_state() will do nothing since it is already
detached state. So the tick timer device will not be shutdown when CPU
is offline.

Function tick_shutdown() did this because it was originally invoked
on a life CPU and not on the outgoing CPU. Now this function is called
on the outgoing CPU, the hardware device can be accessed.

Here remove state set before calling clockevents_exchange_device(),
its state will be set in function clockevents_switch_state() if it
succeeds to do so.
---
  v2 ... v3:
  1. Remove parameter cpu in function tick_shutdown() since it is called
     on the outgoing CPU.
  2. Modify stale comments about tick_shutdown().

  v1 ... v2:
  1. Add Fixes tag in patch 1 since those commits removed shutdown calls
     made from drivers that assumed the timer core would do so.

  2. Remove clockevents shutdown call on LoongArch cpu offline
---
Bibo Mao (2):
  tick: Remove unreasonable detached state set in tick_shutdown()
  LoongArch: Remove clockevents shutdown call on offlining

 arch/loongarch/kernel/time.c |  2 --
 kernel/time/clockevents.c    |  2 +-
 kernel/time/tick-common.c    | 16 +++++-----------
 kernel/time/tick-internal.h  |  2 +-
 4 files changed, 7 insertions(+), 15 deletions(-)


base-commit: d1d10cea0895264cc3769e4d9719baa94f4b250b
-- 
2.39.3