[coreboot-gerrit] Change in coreboot[master]: cpu/x86/mp_init: Increase AP check-in timeout to 1second

[Furquan Shaikh (Code Review)]

Furquan Shaikh has uploaded this change for review. ( https://review.coreboot.org/24965


Change subject: cpu/x86/mp_init: Increase AP check-in timeout to 1second
......................................................................

cpu/x86/mp_init: Increase AP check-in timeout to 1second

Currently, the AP check-in timeout in bsp_do_flight_plan is set to
100ms. However, as the number of APs increases, contention could
increase especially for resource like UART. This led to MP record
timeout issues on KBL platform with 7 APs and serial-console enabled
BIOS image.

This change increases the timeout value to 1 second to be on the safer
side and let APs check-in before continuing boot.

BUG=b:74085891
TEST=Verified that MP record timeout is not observed anymore on Nami.

Change-Id: I979c11a10e6888aef0f71b5632ea803a67bbb0ff
Signed-off-by: Furquan Shaikh <furquan at google.com>
---
M src/cpu/x86/mp_init.c
1 file changed, 6 insertions(+), 1 deletion(-)



  git pull ssh://review.coreboot.org:29418/coreboot refs/changes/65/24965/1

diff --git a/src/cpu/x86/mp_init.c b/src/cpu/x86/mp_init.c
index 92eb722..06e30b6 100644
--- a/src/cpu/x86/mp_init.c
+++ b/src/cpu/x86/mp_init.c
@@ -539,7 +539,12 @@
 {
 	int i;
 	int ret = 0;
-	const int timeout_us = 100000;
+	/*
+	 * Set timeout to wait for APs to a huge value (=1 second) since it
+	 * could take a longer time for APs to check-in as the number of APs
+	 * increases (contention for resources like UART also increases).
+	 */
+	const int timeout_us = 1000000;
 	const int step_us = 100;
 	int num_aps = mp_params->num_cpus - 1;
 

-- 
To view, visit https://review.coreboot.org/24965
To unsubscribe, or for help writing mail filters, visit https://review.coreboot.org/settings

Gerrit-Project: coreboot
Gerrit-Branch: master
Gerrit-MessageType: newchange
Gerrit-Change-Id: I979c11a10e6888aef0f71b5632ea803a67bbb0ff
Gerrit-Change-Number: 24965
Gerrit-PatchSet: 1
Gerrit-Owner: Furquan Shaikh <furquan at google.com>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.coreboot.org/pipermail/coreboot-gerrit/attachments/20180302/a61a8f55/attachment.html>