1 files changed, 27 insertions, 1 deletions

diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index c17fefc77345..ad44b40fe284 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -20,6 +20,7 @@
 #include <linux/device.h>
 #include <linux/delay.h>
 #include <linux/dma-mapping.h>
+#include <linux/init.h>
 #include <linux/module.h>
 #include <linux/kthread.h>
 #include <linux/wait.h>
@@ -53,6 +54,7 @@ static DEFINE_MUTEX(deferred_probe_mutex);
 static LIST_HEAD(deferred_probe_pending_list);
 static LIST_HEAD(deferred_probe_active_list);
 static atomic_t deferred_trigger_count = ATOMIC_INIT(0);
+static bool initcalls_done;
 
 /*
  * In some cases, like suspend to RAM or hibernation, It might be reasonable
@@ -62,6 +64,26 @@ static atomic_t deferred_trigger_count = ATOMIC_INIT(0);
 static bool defer_all_probes;
 
 /*
+ * For initcall_debug, show the deferred probes executed in late_initcall
+ * processing.
+ */
+static void deferred_probe_debug(struct device *dev)
+{
+        ktime_t calltime, delta, rettime;
+        unsigned long long duration;
+
+        printk(KERN_DEBUG "deferred probe %s @ %i\n", dev_name(dev),
+               task_pid_nr(current));
+        calltime = ktime_get();
+        bus_probe_device(dev);
+        rettime = ktime_get();
+        delta = ktime_sub(rettime, calltime);
+        duration = (unsigned long long) ktime_to_ns(delta) >> 10;
+        printk(KERN_DEBUG "deferred probe %s returned after %lld usecs\n",
+               dev_name(dev), duration);
+}
+
+/*
  * deferred_probe_work_func() - Retry probing devices in the active list.
  */
 static void deferred_probe_work_func(struct work_struct *work)
@@ -106,7 +128,10 @@ static void deferred_probe_work_func(struct work_struct *work)
                 device_pm_unlock();
 
                 dev_dbg(dev, "Retrying from deferred list\n");
-                bus_probe_device(dev);
+                if (initcall_debug && !initcalls_done)
+                        deferred_probe_debug(dev);
+                else
+                        bus_probe_device(dev);
 
                 mutex_lock(&deferred_probe_mutex);
 
@@ -215,6 +240,7 @@ static int deferred_probe_initcall(void)
         driver_deferred_probe_trigger();
         /* Sort as many dependencies as possible before exiting initcalls */
         flush_work(&deferred_probe_work);
+        initcalls_done = true;
         return 0;
 }
 late_initcall(deferred_probe_initcall);