Re: [PATCH 3/3] arm64: dts: qcom: qcm2290: Hook up MPM

[Maulik Shah (mkshah)]

On 7/15/2026 11:44 AM, Marek Szyprowski wrote:
> On 14.07.2026 15:29, Maulik Shah (mkshah) wrote:
>> On 7/14/2026 6:34 PM, Ulf Hansson wrote:
>>> On Thu, Jul 9, 2026 at 1:41 PM Marek Szyprowski
>>> <m.szyprowski@xxxxxxxxxxx> wrote:
>> [...]
>>
>>> Without detailed HW expertise (still learning about the UnoQ), it
>>> looks to me that the HW may have been modelled upside down.
>>>
>>> The power-domain-cpu-cluster should probably *not* be the consumer of
>>> the mpm, but rather the opposite. This is how qcom,rpmh-rsc works, for
>>> example.
>> Agree, There is a series [1] sent out to fix modeling similar to how rpmh-rsc works.
>>
>> [1] https://lore.kernel.org/lkml/20260713-b4-shikra_lpm_addition-v1-0-3d858df2cbbf@xxxxxxxxxxxxxxxx/
> Indeed that series fixes the modelling issue, but it doesn't change much
> from the spinlock vs. raw_spinlock perspective. There is still the
> 'invalid wait context' issue there, because mbox API cannot be properly
> called from cpu_pm_notifier (which use raw_notifier internally):

Okay, i see why series [1] did not help for agatti due to fallback on CPU PM notification.

On PREEMPT_RT kernel, GENPD is marked as always RPM always on,
So MPM driver never get the .power_off callback it registered for and hence MPM irqchip won't invoke mbox_() APIs.

from drivers/cpuidle/cpuidle-psci-domain.c,

        /*
         * On a PREEMPT_RT based configuration the domain idle states are
         * supported, but only during system-wide suspend.
         */
            if (IS_ENABLED(CONFIG_PREEMPT_RT))
                        pd->flags |= GENPD_FLAG_RPM_ALWAYS_ON;

The series [1] fallbacks to CPU_PM based notification if "power-domains" property is not added.
having a power-domains property would have avoided the BUG for agatti on RT kernel.

Agatti device tree change in the series [2] only removed power-domain-cells# but did not add power-domains = <&cluster_pd>;
with the reason that qrb2210-rb1.dts had deleted "cluster_pd" however qrb2210-arduino-imola.dts still have it.

so below change on top of [1] series would avoid the BUG from mpm_cpu_pm_callback().

--- a/arch/arm64/boot/dts/qcom/agatti.dtsi
+++ b/arch/arm64/boot/dts/qcom/agatti.dtsi
@@ -281,6 +281,7 @@ mpm: interrupt-controller {
                        interrupt-controller;
                        #interrupt-cells = <2>;
                        interrupt-parent = <&intc>;
+                       power-domains = <&cluster_pd>;
                        qcom,mpm-pin-count = <96>;
                        qcom,mpm-pin-map = <2 275>,  /* TSENS0 uplow */
                                           <5 296>,  /* Soundwire master_irq */
diff --git a/arch/arm64/boot/dts/qcom/qrb2210-rb1.dts b/arch/arm64/boot/dts/qcom/qrb2210-rb1.dts
index bf6fb12ad990..7dc2cade0a7f 100644
--- a/arch/arm64/boot/dts/qcom/qrb2210-rb1.dts
+++ b/arch/arm64/boot/dts/qcom/qrb2210-rb1.dts
@@ -246,6 +246,10 @@ &cpu_pd3 {

 /delete-node/ &cluster_pd;

+&mpm {
+       /delete-property/ power-domains;
+};
+

[2] https://lore.kernel.org/linux-arm-msm/20260713-b4-shikra_lpm_addition-v1-0-3d858df2cbbf@xxxxxxxxxxxxxxxx/T/#m5bbdb535424c38209cc08e6afeae5e3aac9f6cc0

Thanks,
Maulik

> 
> =============================
> [ BUG: Invalid wait context ]
> 7.2.0-rc3-next-20260714+ #16842 Not tainted
> -----------------------------
> swapper/3/0 is trying to lock:
> ffff0000008ac408 (&chan->lock){....}-{3:3}, at: mbox_send_message+0x3c/0x15c
> other info that might help us debug this:
> context-{5:5}
> locks held by swapper/3/0: 1, last CPU#3:
>  #0: ffffd99263a61228 (cpu_pm_notifier.lock){....}-{2:2}, at: cpu_pm_enter+0x28/0x78
> stack backtrace:
> CPU: 3 UID: 0 PID: 0 Comm: swapper/3 Not tainted 7.2.0-rc3-next-20260714+ #16842 PREEMPT
> Hardware name: Arduino UnoQ (DT)
> Call trace:
>  show_stack+0x18/0x24 (C)
>  dump_stack_lvl+0x8c/0xcc
>  dump_stack+0x18/0x24
>  __lock_acquire+0x928/0x1f90
>  lock_acquire+0x2b8/0x3ec
>  _raw_spin_lock_irqsave+0x60/0x88
>  mbox_send_message+0x3c/0x15c
>  handle_rpm_notification+0x58/0x114
>  mpm_cpu_pm_callback+0x9c/0xdc
>  notifier_call_chain+0xa0/0x234
>  raw_notifier_call_chain_robust+0x48/0xa8
>  cpu_pm_enter+0x40/0x78
>  __psci_enter_domain_idle_state.isra.0+0x48/0x470
>  psci_enter_domain_idle_state+0x18/0x24
>  cpuidle_enter_state+0xbc/0x428
>  cpuidle_enter+0x38/0x50
>  do_idle+0x158/0x324
>  cpu_startup_entry+0x38/0x3c
>  secondary_start_kernel+0x138/0x158
>  __secondary_switched+0xc0/0xc4
> 
> Best regards