suspend: fix freeze hangup which caused by insmod [1/1]

PD#TV-10472

Problem:
When system on, enter freeze mode lead to flush deferd probe.
Init.rc also run insmod in parallel, if insmod task
atomic_inc(&probe_count), and this task is freezed,
deadlock happends.

Solution:
Move flush deferd probe action before freeze task

Verify:
X32A0-T972

Change-Id: I8949db32aea14e2da37e77658a9c999af39e2c83
Signed-off-by: Qiufang Dai <qiufang.dai@amlogic.com>

2 files changed, 27 insertions, 3 deletions

diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index 7637314..c54fced 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -966,9 +966,10 @@ void dpm_complete(pm_message_t state)
 	}
 	list_splice(&list, &dpm_list);
 	mutex_unlock(&dpm_list_mtx);
-
+#ifndef CONFIG_AMLOGIC_MODIFY
 	/* Allow device probing and trigger re-probing of deferred devices */
 	device_unblock_probing();
+#endif
 	trace_suspend_resume(TPS("dpm_complete"), state.event, false);
 }
 
@@ -1639,7 +1640,7 @@ int dpm_prepare(pm_message_t state)
 
 	trace_suspend_resume(TPS("dpm_prepare"), state.event, true);
 	might_sleep();
-
+#ifndef CONFIG_AMLOGIC_MODIFY
 	/*
 	 * Give a chance for the known devices to complete their probes, before
 	 * disable probing of devices. This sync point is important at least
@@ -1653,7 +1654,7 @@ int dpm_prepare(pm_message_t state)
 	 * instead. The normal behavior will be restored in dpm_complete().
 	 */
 	device_block_probing();
-
+#endif
 	mutex_lock(&dpm_list_mtx);
 	while (!list_empty(&dpm_list)) {
 		struct device *dev = to_device(dpm_list.next);
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index 678e8fa..71050f5 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -33,6 +33,9 @@
 #include <linux/wakeup_reason.h>
 
 #include "power.h"
+#ifdef CONFIG_AMLOGIC_MODIFY
+#include "../../drivers/base/base.h"
+#endif
 
 const char *pm_labels[] = { "mem", "standby", "freeze", NULL };
 const char *pm_states[PM_SUSPEND_MAX];
@@ -289,6 +292,22 @@ static int suspend_prepare(suspend_state_t state)
 		goto Finish;
 	}
 
+#ifdef CONFIG_AMLOGIC_MODIFY
+	/*
+	 * Give a chance for the known devices to complete their probes, before
+	 * disable probing of devices. This sync point is important at least
+	 * at boot time + hibernation restore.
+	 */
+	wait_for_device_probe();
+	/*
+	 * It is unsafe if probing of devices will happen during suspend or
+	 * hibernation and system behavior will be unpredictable in this case.
+	 * So, let's prohibit device's probing here and defer their probes
+	 * instead. The normal behavior will be restored in dpm_complete().
+	 */
+	device_block_probing();
+#endif
+
 	trace_suspend_resume(TPS("freeze_processes"), 0, true);
 	error = suspend_freeze_processes();
 	trace_suspend_resume(TPS("freeze_processes"), 0, false);
@@ -500,6 +519,10 @@ int suspend_devices_and_enter(suspend_state_t state)
 static void suspend_finish(void)
 {
 	suspend_thaw_processes();
+#ifdef CONFIG_AMLOGIC_MODIFY
+	/* Allow device probing and trigger re-probing of deferred devices */
+	device_unblock_probing();
+#endif
 	pm_notifier_call_chain(PM_POST_SUSPEND);
 	pm_restore_console();
 }