On Mon, 19 Dec 2022 at 16:15, Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx> wrote: > > The PSCI cpuidle power domain in power_off callback uses > __this_cpu_write() so it is PREEMPT_RT safe. This allows to use it in > Realtime kernels and solves errors like: > > BUG: scheduling while atomic: swapper/2/0/0x00000002 > Hardware name: Qualcomm Technologies, Inc. Robotics RB5 (DT) > Call trace: > dump_backtrace.part.0+0xe0/0xf0 > show_stack+0x18/0x40 > dump_stack_lvl+0x68/0x84 > dump_stack+0x18/0x34 > __schedule_bug+0x60/0x80 > __schedule+0x628/0x800 > schedule_rtlock+0x28/0x5c > rtlock_slowlock_locked+0x360/0xd30 > rt_spin_lock+0x88/0xb0 > genpd_lock_nested_spin+0x1c/0x30 > genpd_power_off.part.0.isra.0+0x20c/0x2a0 > genpd_runtime_suspend+0x150/0x2bc > __rpm_callback+0x48/0x170 > rpm_callback+0x6c/0x7c > rpm_suspend+0x108/0x660 > __pm_runtime_suspend+0x4c/0x8c > __psci_enter_domain_idle_state.constprop.0+0x54/0xe0 > psci_enter_domain_idle_state+0x18/0x2c > cpuidle_enter_state+0x8c/0x4e0 > cpuidle_enter+0x38/0x50 > do_idle+0x248/0x2f0 > cpu_startup_entry+0x24/0x30 > secondary_start_kernel+0x130/0x154 > __secondary_switched+0xb0/0xb4 > > Cc: Adrien Thierry <athierry@xxxxxxxxxx> > Cc: Brian Masney <bmasney@xxxxxxxxxx> > Cc: linux-rt-users@xxxxxxxxxxxxxxx > Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx> > --- > drivers/cpuidle/cpuidle-psci-domain.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/cpuidle/cpuidle-psci-domain.c b/drivers/cpuidle/cpuidle-psci-domain.c > index c80cf9ddabd8..d15a91fb7048 100644 > --- a/drivers/cpuidle/cpuidle-psci-domain.c > +++ b/drivers/cpuidle/cpuidle-psci-domain.c > @@ -62,7 +62,8 @@ static int psci_pd_init(struct device_node *np, bool use_osi) > if (!pd_provider) > goto free_pd; > > - pd->flags |= GENPD_FLAG_IRQ_SAFE | GENPD_FLAG_CPU_DOMAIN; > + pd->flags |= GENPD_FLAG_IRQ_SAFE | GENPD_FLAG_RT_SAFE | \ > + GENPD_FLAG_CPU_DOMAIN; My main concern with this, is that it will affect the parent domains too. Whether those would be able to use the GENPD_FLAG_RT_SAFE or not, is a different story. In one way or the other, I think it would be better to limit the GENPD_FLAG_RT_SAFE to be used only for PREEMPT_RT kernels. > > /* Allow power off when OSI has been successfully enabled. */ > if (use_osi) > -- > 2.34.1 > Kind regards Uffe
