linux-kernel - [PATCH v2] chrome/cros_ec: Handle events during suspend after resume completion

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Message-ID: <20240429121343.v2.1.If2e0cef959f1f6df9f4d1ab53a97c54aa54208af@changeid>
Date: Mon, 29 Apr 2024 12:13:45 -0600
From: Karthikeyan Ramasubramanian <kramasub@...omium.org>
To: LKML <linux-kernel@...r.kernel.org>
Cc: Karthikeyan Ramasubramanian <kramasub@...omium.org>,
	stable@...r.kernel.org,
	Lalith Rajendran <lalithkraj@...omium.org>,
	chrome-platform@...ts.linux.dev,
	Benson Leung <bleung@...omium.org>,
	Guenter Roeck <groeck@...omium.org>,
	Tzung-Bi Shih <tzungbi@...nel.org>
Subject: [PATCH v2] chrome/cros_ec: Handle events during suspend after resume completion

Commit 47ea0ddb1f56 ("platform/chrome: cros_ec_lpc: Separate host
command and irq disable") re-ordered the resume sequence. Before that
change, cros_ec resume sequence is:
1) Enable IRQ
2) Send resume event
3) Handle events during suspend

After commit 47ea0ddb1f56 ("platform/chrome: cros_ec_lpc: Separate host
command and irq disable"), cros_ec resume sequence is:
1) Enable IRQ
2) Handle events during suspend
3) Send resume event.

This re-ordering leads to delayed handling of any events queued between
items 2) and 3) with the updated sequence. Also in certain platforms, EC
skips triggering interrupt for certain events eg. mkbp events until the
resume event is received. Such events are stuck in the host event queue
indefinitely. This change puts back the original order to avoid any
delay in handling the pending events.

Fixes: 47ea0ddb1f56 ("platform/chrome: cros_ec_lpc: Separate host command and irq disable")
Cc: stable@...r.kernel.org
Cc: Lalith Rajendran <lalithkraj@...omium.org>
Cc: chrome-platform@...ts.linux.dev
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@...omium.org>
---

Changes in v2:
- Updated the commit message with the right problem description

 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