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

Adrian Hunter
2026-01-29T20:42:59Z

On 29/01/2026 21:56, Frank Li wrote:
> 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.

It should be effective.

rpm_suspend() recalculates the autosuspend expiry time based on
last_busy (see pm_runtime_autosuspend_expiration()) and restarts
the timer is it is in the future.

>
> 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?

Just premature runtime suspension inconsistent with autosuspend_delay.

>
> Frank
>
>>
>> Signed-off-by: Adrian Hunter <adrian.hunter@intel.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
>>