Re: [PATCH 3/3] Input: snvs_pwrkey - report press event in interrupt handler

Frank Li
2026-03-31T14:11:18Z

On Tue, Mar 31, 2026 at 06:46:55PM +0800, Joy Zou wrote:
> On Thu, Mar 26, 2026 at 03:57:27PM -0400, Frank Li wrote:
> > On Thu, Mar 26, 2026 at 06:39:40PM +0800, Joy Zou wrote:
> > > On some boards such as i.MX8MQ-EVK, the PCIe driver may take up to
> > > 200ms to restore the PCIe link during the no_irq resume phase. This
> > > causes key press events to be lost because the key may be released
> > > before the timer starts running, as interrupts are disabled during
> > > this 200ms window.
> >
> > if irq disable, how imx_snvs_pwrkey_interrupt get run?
> >
> Thank you for your comments. I might have missed some details in my commit
> message. Could you please review the description below and let me know if
> it's clear and comprehensive enough?
>
> The driver implements debounce protection using a timer-based mechanism:
> when a key interrupt occurs, a timer is scheduled to verify the key state
> after DEBOUNCE_TIME before reporting the event. This works well during
> normal operation.
>
> However, key press events can be lost during system resume on platforms
> like i.MX8MQ-EVK because:
> 1. During the no_irq resume phase, PCIe driver restoration can take up to
> 200ms with IRQs disabled.
> 2. The power key interrupt remains pending during the no_irq phase.
> 3. If the key is released before IRQs are re-enabled, the timer eventually
> runs but sees the key as released and skips reporting the event.
>
> Report key press events directly in interrupt handler to prevent event
> loss during system suspend. This is safe because:
>
> 1. Only one event is reported per suspend cycle.
> 2. Normal operation retains the existing timer-based debounce mechanism.

much better. Thanks

Frank

> BR
> Joy Zou
> > Frank
> > >
> > > Report key press events directly in interrupt handler to prevent event
> > > loss during system suspend.
> > >
> > > Signed-off-by: Joy Zou <joy.zou@nxp.com>
> > > ---
> > > drivers/input/keyboard/snvs_pwrkey.c | 10 ++++++++++
> > > 1 file changed, 10 insertions(+)
> > >
> > > diff --git a/drivers/input/keyboard/snvs_pwrkey.c b/drivers/input/keyboard/snvs_pwrkey.c
> > > index bab3ab57fdac77256be75a080773ea99372ec9c7..b557c1618d7369e872c6ce708a7b3017264ee385 100644
> > > --- a/drivers/input/keyboard/snvs_pwrkey.c
> > > +++ b/drivers/input/keyboard/snvs_pwrkey.c
> > > @@ -78,6 +78,16 @@ static irqreturn_t imx_snvs_pwrkey_interrupt(int irq, void *dev_id)
> > >
> > > pm_wakeup_event(input->dev.parent, 0);
> > >
> > > + /*
> > > + * Report key press events directly in interrupt handler to prevent event
> > > + * loss during system suspend.
> > > + */
> > > + if (pdev->dev.power.is_suspended) {
> > > + pdata->keystate = 1;
> > > + input_report_key(input, pdata->keycode, 1);
> > > + input_sync(input);
> > > + }
> > > +
> > > regmap_read(pdata->snvs, SNVS_LPSR_REG, &lp_status);
> > > if (lp_status & SNVS_LPSR_SPO) {
> > > if (pdata->minor_rev == 0) {
> > >
> > > --
> > > 2.37.1
> > >