Subject: [PATCH v1] chrome/cros_ec: Handle events during suspend after resume completion

On boards where EC IRQ is not wake capable, EC does not trigger IRQ to
signal any non-wake events until EC receives host resume event.
Commit 47ea0ddb1f56 ("platform/chrome: cros_ec_lpc: Separate host
command and irq disable") separated enabling IRQ and sending resume
event host command into early_resume and resume_complete stages
respectively. This separation leads to host not handling certain events
posted during a small time window between early_resume and
resume_complete stages. This change moves handling all events that
happened during suspend after sending host resume event.

Fixes: 47ea0ddb1f56 ("platform/chrome: cros_ec_lpc: Separate host command and irq disable")
Cc: [email protected]
Cc: Lalith Rajendran <[email protected]>
Cc: [email protected]
Signed-off-by: Karthikeyan Ramasubramanian <[email protected]>
---

drivers/platform/chrome/cros_ec.c | 17 +++++++++--------
1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/drivers/platform/chrome/cros_ec.c b/drivers/platform/chrome/cros_ec.c
index badc68bbae8cc..41714df053916 100644
--- a/drivers/platform/chrome/cros_ec.c
+++ b/drivers/platform/chrome/cros_ec.c
@@ -432,6 +432,12 @@ static void cros_ec_send_resume_event(struct cros_ec_device *ec_dev)
void cros_ec_resume_complete(struct cros_ec_device *ec_dev)
{
cros_ec_send_resume_event(ec_dev);
+ /*
+ * Let the mfd devices know about events that occur during
+ * suspend. This way the clients know what to do with them.
+ */
+ cros_ec_report_events_during_suspend(ec_dev);
+
}
EXPORT_SYMBOL(cros_ec_resume_complete);

@@ -442,12 +448,6 @@ static void cros_ec_enable_irq(struct cros_ec_device *ec_dev)

if (ec_dev->wake_enabled)
disable_irq_wake(ec_dev->irq);
-
- /*
- * Let the mfd devices know about events that occur during
- * suspend. This way the clients know what to do with them.
- */
- cros_ec_report_events_during_suspend(ec_dev);
}

/**
@@ -475,8 +475,9 @@ EXPORT_SYMBOL(cros_ec_resume_early);
*/
int cros_ec_resume(struct cros_ec_device *ec_dev)
{
- cros_ec_enable_irq(ec_dev);
- cros_ec_send_resume_event(ec_dev);
+ cros_ec_resume_early(ec_dev);
+ cros_ec_resume_complete(ec_dev);
+
return 0;
}
EXPORT_SYMBOL(cros_ec_resume);
--
2.44.0.769.g3c40516874-goog



2024-04-26 04:39:35

by Tzung-Bi Shih

[permalink] [raw]
Subject: Re: [PATCH v1] chrome/cros_ec: Handle events during suspend after resume completion

On Thu, Apr 25, 2024 at 02:37:11PM -0600, Karthikeyan Ramasubramanian wrote:
> On boards where EC IRQ is not wake capable, EC does not trigger IRQ to
> signal any non-wake events until EC receives host resume event.

The sentence looks irrelevant to the fix. Presumably, EC should send those
pending non-wake events after it receives host resume event.

> Commit 47ea0ddb1f56 ("platform/chrome: cros_ec_lpc: Separate host
> command and irq disable") separated enabling IRQ and sending resume
> event host command into early_resume and resume_complete stages
> respectively. This separation leads to host not handling certain events
> posted during a small time window between early_resume and
> resume_complete stages. This change moves handling all events that
> happened during suspend after sending host resume event.

The regression you see is probably not due to the "separation" but an unwanted
code reorder.

Before 47ea0ddb1f56[1], a resume is:
1) Enable IRQ.
2) Send resume event.
3) Handle pending events.


After 47ea0ddb1f56[2], a resume is:
1) Enable IRQ.
2) Handle pending events.
3) Send resume event.

If there are some more events pending between 2) and 3), they would be handled
further late.

[1]: https://elixir.bootlin.com/linux/v6.6/source/drivers/platform/chrome/cros_ec.c#L381
[2]: https://elixir.bootlin.com/linux/v6.7/source/drivers/platform/chrome/cros_ec.c#L438


I see what the patch tries to fix but the commit message makes less sense to
me. Please fix accordingly.