[coreboot-gerrit] Change in coreboot[master]: mb/google/{auron,slippy}/ec: clear pending events on S3 wakeup

[Patrick Georgi (Code Review)]

Patrick Georgi has submitted this change. ( https://review.coreboot.org/c/coreboot/+/38984 )

Change subject: mb/google/{auron,slippy}/ec: clear pending events on S3 wakeup
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mb/google/{auron,slippy}/ec: clear pending events on S3 wakeup

Commit 6ae8b50 [chromeec: Depend on events_copy_b to identify wake source]
partially broke resume from suspend on Auron and Slippy variants when
multiple events exist in the EC event queue. In the case of the device
suspending manually and then subsequently having the lid closed, the device
will be stuck in a resume/suspend/resume loop until the device is forcibly
powered down.

Mitigate this by clearing any pending EC events on S3 wakeup.

Test: build/boot several Auron/Slippy variants, test suspend/resume functional
with both single and multiple events in EC event queue.

Change-Id: I7ec9ec575d41c5b7522c4e13fc32b0b7c77d20d9
Signed-off-by: Matt DeVillier 
Reviewed-on: https://review.coreboot.org/c/coreboot/+/38984
Tested-by: build bot (Jenkins) 
Reviewed-by: Furquan Shaikh 
Reviewed-by: Paul Menzel 
---
M src/mainboard/google/auron/ec.c
M src/mainboard/google/slippy/ec.c
2 files changed, 16 insertions(+), 2 deletions(-)

Approvals:
  build bot (Jenkins): Verified
  Paul Menzel: Looks good to me, but someone else must approve
  Furquan Shaikh: Looks good to me, approved

diff --git a/src/mainboard/google/auron/ec.c b/src/mainboard/google/auron/ec.c
index 3fc5373..0589864 100644
--- a/src/mainboard/google/auron/ec.c
+++ b/src/mainboard/google/auron/ec.c
@@ -29,10 +29,17 @@
    	.s5_wake_events = MAINBOARD_EC_S5_WAKE_EVENTS,
    };

+	int s3_wakeup = acpi_is_wakeup_s3();
+
    printk(BIOS_DEBUG, "mainboard_ec_init\n");
    post_code(0xf0);

-	google_chromeec_events_init(&info, acpi_is_wakeup_s3());
+	google_chromeec_events_init(&info, s3_wakeup);
+	if (s3_wakeup) {
+		/* Clear pending events. */
+		while (google_chromeec_get_event() != 0)
+			;
+	}

post_code(0xf1);
 }
diff --git a/src/mainboard/google/slippy/ec.c b/src/mainboard/google/slippy/ec.c
index f8ab6b8..e296575 100644
--- a/src/mainboard/google/slippy/ec.c
+++ b/src/mainboard/google/slippy/ec.c
@@ -28,10 +28,17 @@
    	.s5_wake_events = MAINBOARD_EC_S5_WAKE_EVENTS,
    };

+	int s3_wakeup = acpi_is_wakeup_s3();
+
    printk(BIOS_DEBUG, "mainboard_ec_init\n");
    post_code(0xf0);

-	google_chromeec_events_init(&info, acpi_is_wakeup_s3());
+	google_chromeec_events_init(&info, s3_wakeup);
+	if (s3_wakeup) {
+		/* Clear pending events. */
+		while (google_chromeec_get_event() != 0)
+			;
+	}

post_code(0xf1);
 }