[PATCH] cpuidle-haltpoll: make haltpoll aware of 'idle=' override

From: Zhenzhong Duan
Date: Wed Oct 16 2019 - 20:41:43 EST

Currenly haltpoll isn't aware of the 'idle=' override, the priority is
'idle=poll' > haltpoll > 'idle=halt'. When 'idle=poll' is used, cpuidle
driver is bypassed but current_driver in sys still shows 'haltpoll'.

When 'idle=halt' is used, haltpoll take precedence and make 'idle=halt'
no effect.

Add a check to not load haltpoll driver if there is 'idle=' and haltpoll
is built in. If haltpoll is built as a module, still give a chance for
admin to use it despite 'idle='.

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@xxxxxxxxxx>
Signed-off-by: Joao Martins <joao.m.martins@xxxxxxxxxx>
drivers/cpuidle/cpuidle-haltpoll.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/drivers/cpuidle/cpuidle-haltpoll.c b/drivers/cpuidle/cpuidle-haltpoll.c
index 932390b..00e9821 100644
--- a/drivers/cpuidle/cpuidle-haltpoll.c
+++ b/drivers/cpuidle/cpuidle-haltpoll.c
@@ -95,6 +95,12 @@ static int __init haltpoll_init(void)
int ret;
struct cpuidle_driver *drv = &haltpoll_driver;

+ /* Do not load haltpoll if idle= is passed */
+ if (boot_option_idle_override != IDLE_NO_OVERRIDE)
+ return -ENODEV;

if (!kvm_para_available() ||