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From:   Anup Patel <anup@brainfault.org>
Date:   Mon, 12 Oct 2020 22:32:38 +0530
Message-ID: <CAAhSdy0Jj3+gsto8oj76GkDnm1WYiDFCntM=VuxKtoABGYTK5g@mail.gmail.com>
Subject: Re: [PATCH 1/2] irqchip/sifive-plic: Enable or disable interrupt
 based on its previous setting
To:     Greentime Hu <greentime.hu@sifive.com>
Cc:     Thomas Gleixner <tglx@linutronix.de>,
        Jason Cooper <jason@lakedaemon.net>,
        Marc Zyngier <maz@kernel.org>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        "linux-kernel@vger.kernel.org List" <linux-kernel@vger.kernel.org>,
        linux-riscv <linux-riscv@lists.infradead.org>
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On Mon, Oct 12, 2020 at 7:27 PM Greentime Hu <greentime.hu@sifive.com> wrote:
>
> It will always enable the interrupt after calling plic_set_affinity()
> however it should set to its previous setting. Staying disabled or enabled.
>
> This patch can also fix this pwm hang issue in Unleashed board.
>
> [  919.015783] rcu: INFO: rcu_sched detected stalls on CPUs/tasks:
> [  919.020922] rcu:     0-...0: (0 ticks this GP)
> idle=7d2/1/0x4000000000000002 softirq=1424/1424 fqs=105807
> [  919.030295]  (detected by 1, t=225825 jiffies, g=1561, q=3496)
> [  919.036109] Task dump for CPU 0:
> [  919.039321] kworker/0:1     R  running task        0    30      2 0x00000008
> [  919.046359] Workqueue: events set_brightness_delayed
> [  919.051302] Call Trace:
> [  919.053738] [<ffffffe000930d92>] __schedule+0x194/0x4de
> [  982.035783] rcu: INFO: rcu_sched detected stalls on CPUs/tasks:
> [  982.040923] rcu:     0-...0: (0 ticks this GP)
> idle=7d2/1/0x4000000000000002 softirq=1424/1424 fqs=113325
> [  982.050294]  (detected by 1, t=241580 jiffies, g=1561, q=3509)
> [  982.056108] Task dump for CPU 0:
> [  982.059321] kworker/0:1     R  running task        0    30      2 0x00000008
> [  982.066359] Workqueue: events set_brightness_delayed
> [  982.071302] Call Trace:
> [  982.073739] [<ffffffe000930d92>] __schedule+0x194/0x4de
> [..]
>
> Fixes: bb0fed1c60cc ("irqchip/sifive-plic: Switch to fasteoi flow")
> Signed-off-by: Greentime Hu <greentime.hu@sifive.com>
> ---
>  drivers/irqchip/irq-sifive-plic.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/irqchip/irq-sifive-plic.c b/drivers/irqchip/irq-sifive-plic.c
> index eaa3e9fe54e9..4cc8a2657a6d 100644
> --- a/drivers/irqchip/irq-sifive-plic.c
> +++ b/drivers/irqchip/irq-sifive-plic.c
> @@ -137,6 +137,7 @@ static int plic_set_affinity(struct irq_data *d,
>                              const struct cpumask *mask_val, bool force)
>  {
>         unsigned int cpu;
> +       bool enable;
>         struct cpumask amask;
>         struct plic_priv *priv = irq_get_chip_data(d->irq);
>
> @@ -150,8 +151,10 @@ static int plic_set_affinity(struct irq_data *d,
>         if (cpu >= nr_cpu_ids)
>                 return -EINVAL;
>
> +       enable = !irqd_irq_disabled(d);
>         plic_irq_toggle(&priv->lmask, d, 0);
> -       plic_irq_toggle(cpumask_of(cpu), d, 1);
> +       /* Keep its original setting. */
> +       plic_irq_toggle(cpumask_of(cpu), d, enable);
>
>         irq_data_update_effective_affinity(d, cpumask_of(cpu));
>
> --
> 2.28.0
>
>
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> linux-riscv@lists.infradead.org
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Good catch. Your fix looks good to me.

Reviewed-by: Anup Patel <anup@brainfault.org>

Regards,
Anup