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References: <20220509012121.40031-1-samuel@sholland.org>
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From:   Anup Patel <anup@brainfault.org>
Date:   Mon, 9 May 2022 09:21:09 +0530
Message-ID: <CAAhSdy0U23M1wL9xxh20w23xEY-MjxoxxdXVy50G7p8=eXxWKw@mail.gmail.com>
Subject: Re: [PATCH] clocksource/drivers/riscv: Events are stopped during CPU suspend
To:     Samuel Holland <samuel@sholland.org>
Cc:     Daniel Lezcano <daniel.lezcano@linaro.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Atish Patra <atishp@atishpatra.org>,
        Dmitriy Cherkasov <dmitriy@oss-tech.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, May 9, 2022 at 6:51 AM Samuel Holland <samuel@sholland.org> wrote:
>
> Some implementations of the SBI time extension depend on hart-local
> state (for example, CSRs) that are lost or hardware that is powered
> down when a CPU is suspended. To be safe, the clockevents driver
> cannot assume that timer IRQs will be received during CPU suspend.
>
> Fixes: 62b019436814 ("clocksource: new RISC-V SBI timer driver")
> Signed-off-by: Samuel Holland <samuel@sholland.org>

Looks good to me.

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

Regards,
Anup

> ---
>
>  drivers/clocksource/timer-riscv.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/clocksource/timer-riscv.c b/drivers/clocksource/timer-riscv.c
> index 1767f8bf2013..593d5a957b69 100644
> --- a/drivers/clocksource/timer-riscv.c
> +++ b/drivers/clocksource/timer-riscv.c
> @@ -34,7 +34,7 @@ static int riscv_clock_next_event(unsigned long delta,
>  static unsigned int riscv_clock_event_irq;
>  static DEFINE_PER_CPU(struct clock_event_device, riscv_clock_event) = {
>         .name                   = "riscv_timer_clockevent",
> -       .features               = CLOCK_EVT_FEAT_ONESHOT,
> +       .features               = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_C3STOP,
>         .rating                 = 100,
>         .set_next_event         = riscv_clock_next_event,
>  };
> --
> 2.35.1
>
>
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