fix for device re-loads from resume

patches/4.18/acpi.patch

@@ -1322,3 +1322,53 @@ index 000000000000..7a84340b04bb
 +MODULE_AUTHOR("Jake Day");
 +MODULE_DESCRIPTION("Microsoft Surface Platform Driver");
 +MODULE_LICENSE("GPL");
+diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
+index 87331565e505..d55f949ee25a 100644
+--- a/kernel/power/suspend.c
++++ b/kernel/power/suspend.c
+@@ -520,6 +520,8 @@ int suspend_devices_and_enter(suspend_state_t state)
+ 	goto Resume_devices;
+ }
+ 
++unsigned int resume_delay = 3000;
++
+ /**
+  * suspend_finish - Clean up before finishing the suspend sequence.
+  *
+@@ -528,6 +530,15 @@ int suspend_devices_and_enter(suspend_state_t state)
+  */
+ static void suspend_finish(void)
+ {
++	if (resume_delay) {
++		/* Give kernel threads a head start, such that usb-storage
++		 * can detect devices before syslog attempts to write log
++		 * messages from the suspend code.
++		 */
++		thaw_kernel_threads();
++		pr_debug("PM: Sleeping for %d milliseconds.\n", resume_delay);
++		msleep(resume_delay);
++	}
+ 	suspend_thaw_processes();
+ 	pm_notifier_call_chain(PM_POST_SUSPEND);
+ 	pm_restore_console();
+diff --git a/kernel/sysctl.c b/kernel/sysctl.c
+index 2d9837c0aff4..ac704bf71f45 100644
+--- a/kernel/sysctl.c
++++ b/kernel/sysctl.c
+@@ -308,7 +308,16 @@ static int min_extfrag_threshold;
+ static int max_extfrag_threshold = 1000;
+ #endif
+ 
++extern unsigned int resume_delay;
++
+ static struct ctl_table kern_table[] = {
++	{
++		.procname	= "resume_delay",
++		.data		= &resume_delay,
++		.maxlen		= sizeof(unsigned int),
++		.mode		= 0644,
++		.proc_handler	= proc_dointvec,
++	},
+ 	{
+ 		.procname	= "sched_child_runs_first",
+ 		.data		= &sysctl_sched_child_runs_first,