linux-kernel - Re: [PATCH 3/7] i3c: master: Mark last_busy on IBI when runtime PM is allowed

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Message-ID: <aXu7UduYCweVLxdK@lizhi-Precision-Tower-5810>
Date: Thu, 29 Jan 2026 14:56:01 -0500
From: Frank Li <Frank.li@....com>
To: Adrian Hunter <adrian.hunter@...el.com>
Cc: alexandre.belloni@...tlin.com, linux-i3c@...ts.infradead.org,
	linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org
Subject: Re: [PATCH 3/7] i3c: master: Mark last_busy on IBI when runtime PM
 is allowed

On Thu, Jan 29, 2026 at 08:18:37PM +0200, Adrian Hunter wrote:
> When an IBI can be received after the controller is
> pm_runtime_put_autosuspend()'ed, the interrupt may occur just before the
> device is auto‑suspended.  In such cases, the runtime PM core may not see
> any recent activity and may suspend the device earlier than intended.
>
> Mark the controller as last busy whenever an IBI is queued (when
> rpm_ibi_allowed is set) so that the auto-suspend delay correctly reflects
> recent bus activity and avoids premature suspension.

look like this can't resolve problem. pm_runtime_mark_last_busy() just
change dev->power.last_busy. If suspend before it, nothing happen.

irq use thread irq, in irq thread call pm_runtime_resume() if needs.

And this function call by irq handle, just put to work queue, what's impact
if do nothing here?

Frank

>
> Signed-off-by: Adrian Hunter <adrian.hunter@...el.com>
> ---
>  drivers/i3c/master.c | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
> index bcc493dc9d04..dcc07ebc50a2 100644
> --- a/drivers/i3c/master.c
> +++ b/drivers/i3c/master.c
> @@ -2721,9 +2721,14 @@ static void i3c_master_unregister_i3c_devs(struct i3c_master_controller *master)
>   */
>  void i3c_master_queue_ibi(struct i3c_dev_desc *dev, struct i3c_ibi_slot *slot)
>  {
> +	struct i3c_master_controller *master = i3c_dev_get_master(dev);
> +
>  	if (!dev->ibi || !slot)
>  		return;
>
> +	if (master->rpm_ibi_allowed)
> +		pm_runtime_mark_last_busy(master->rpm_dev);
> +
>  	atomic_inc(&dev->ibi->pending_ibis);
>  	queue_work(dev->ibi->wq, &slot->work);
>  }
> --
> 2.51.0
>