Re: [PATCH net-next 1/6] net: ipa: don't bother aborting system resume

Paolo Abeni
2024-02-27T10:23:28Z

On Fri, 2024-02-23 at 07:39 -0600, Alex Elder wrote:
> The IPA interrupt can fire if there is data to be delivered to a GSI
> channel that is suspended. This condition occurs in three scenarios.
>
> First, runtime power management automatically suspends the IPA
> hardware after half a second of inactivity. This has nothing
> to do with system suspend, so a SYSTEM IPA power flag is used to
> avoid calling pm_wakeup_dev_event() when runtime suspended.
>
> Second, if the system is suspended, the receipt of an IPA interrupt
> should trigger a system resume. Configuring the IPA interrupt for
> wakeup accomplishes this.
>
> Finally, if system suspend is underway and the IPA interrupt fires,
> we currently call pm_wakeup_dev_event() to abort the system suspend.
>
> The IPA driver correctly handles quiescing the hardware before
> suspending it, so there's really no need to abort a suspend in
> progress in the third case. We can simply quiesce and suspend
> things, and be done.
>
> Incoming data can still wake the system after it's suspended.
> The IPA interrupt has wakeup mode enabled, so if it fires *after*
> we've suspended, it will trigger a wakeup (if not disabled via
> sysfs).
>
> Stop calling pm_wakeup_dev_event() to abort a system suspend in
> progress in ipa_power_suspend_handler().
>
> Signed-off-by: Alex Elder <elder@linaro.org>
> ---
> Note: checkpatch warns: braces {} are not necessary...
>
> drivers/net/ipa/ipa_power.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/ipa/ipa_power.c b/drivers/net/ipa/ipa_power.c
> index 128a816f65237..694bc71e0a170 100644
> --- a/drivers/net/ipa/ipa_power.c
> +++ b/drivers/net/ipa/ipa_power.c
> @@ -220,8 +220,9 @@ void ipa_power_suspend_handler(struct ipa *ipa, enum ipa_irq_id irq_id)
> * system suspend, trigger a system resume.
> */
> if (!__test_and_set_bit(IPA_POWER_FLAG_RESUMED, ipa->power->flags))
> - if (test_bit(IPA_POWER_FLAG_SYSTEM, ipa->power->flags))
> - pm_wakeup_dev_event(&ipa->pdev->dev, 0, true);
> + if (test_bit(IPA_POWER_FLAG_SYSTEM, ipa->power->flags)) {
> + ;
> + }

FTR, I would have dropped the whole 'if' statement above and the
related comment in this patch, saving a few checkpatch warnings. Not a
big deal since the the chunk is removed a few patches later.

Cheers,

Paolo