[PATCH] lib: fwts_pm_method: save t_start for logind outside of logind_on_signal

[Robert Liu]

Buglink: https://bugs.launchpad.net/bugs/1809096

On some systems without logind system-sleep hooks (e.g. Ubuntu Core),
the t_start value sometimes cannot be stored in logind_on_signal()
before s3/s4. The t_start then be updated after system resumed. This
condition makes the s3/s4 duration become 0 and FWTS reports a medium
failure (ShortSuspend) and a high failure (PMActionFailedPreS3).

This commit moves the statement of storing t_start from
logind_on_signal() to fwts_logind_wait_for_resume_from_action() and
eliminate the failures.
Although it will make the timestamp not accurate, but the latency is
quite small and could be ignored.

Signed-off-by: Robert Liu <robert.liu at canonical.com>
---
 src/lib/src/fwts_pm_method.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/lib/src/fwts_pm_method.c b/src/lib/src/fwts_pm_method.c
index e9faede..143cd5c 100644
--- a/src/lib/src/fwts_pm_method.c
+++ b/src/lib/src/fwts_pm_method.c
@@ -129,7 +129,6 @@ static void logind_on_signal(
 		if (status) {
 			char buffer[50];
 
-			(void)time(&(fwts_settings->t_start));
 			snprintf(buffer, sizeof(buffer), "Starting fwts %s\n",
 				is_s3 ? "suspend" : "hibernate");
 			(void)fwts_klog_write(fwts_settings->fw, buffer);
@@ -318,10 +317,12 @@ int fwts_logind_wait_for_resume_from_action(
 	/* Start the main loop */
 	fwts_settings->gmainloop = g_main_loop_new(NULL, FALSE);
 	if (fwts_settings->gmainloop) {
+		(void)time(&(fwts_settings->t_start));
 		g_timeout_add(1, logind_do, fwts_settings);
 
 		g_main_loop_run(fwts_settings->gmainloop);
-		duration = (int)(fwts_settings->t_end - fwts_settings->t_start);
+		if (fwts_settings->t_end > 0)
+			duration = (int)(fwts_settings->t_end - fwts_settings->t_start);
 
 		/* Optional, as it will be freed together with the struct */
 		g_main_loop_unref(fwts_settings->gmainloop);
-- 
2.7.4