1 files changed, 35 insertions, 1 deletions

diff --git a/drivers/base/power/trace.c b/drivers/base/power/trace.c
index 0a1a2c4dbc6e..9f4258df4cfd 100644
--- a/drivers/base/power/trace.c
+++ b/drivers/base/power/trace.c
@@ -188,8 +188,10 @@ static int show_file_hash(unsigned int value)
 static int show_dev_hash(unsigned int value)
 {
         int match = 0;
-        struct list_head *entry = dpm_list.prev;
+        struct list_head *entry;
 
+        device_pm_lock();
+        entry = dpm_list.prev;
         while (entry != &dpm_list) {
                 struct device * dev = to_device(entry);
                 unsigned int hash = hash_string(DEVSEED, dev_name(dev), DEVHASH);
@@ -199,11 +201,43 @@ static int show_dev_hash(unsigned int value)
                 }
                 entry = entry->prev;
         }
+        device_pm_unlock();
         return match;
 }
 
 static unsigned int hash_value_early_read;
 
+int show_trace_dev_match(char *buf, size_t size)
+{
+        unsigned int value = hash_value_early_read / (USERHASH * FILEHASH);
+        int ret = 0;
+        struct list_head *entry;
+
+        /*
+         * It's possible that multiple devices will match the hash and we can't
+         * tell which is the culprit, so it's best to output them all.
+         */
+        device_pm_lock();
+        entry = dpm_list.prev;
+        while (size && entry != &dpm_list) {
+                struct device *dev = to_device(entry);
+                unsigned int hash = hash_string(DEVSEED, dev_name(dev),
+                                                DEVHASH);
+                if (hash == value) {
+                        int len = snprintf(buf, size, "%s\n",
+                                            dev_driver_string(dev));
+                        if (len > size)
+                                len = size;
+                        buf += len;
+                        ret += len;
+                        size -= len;
+                }
+                entry = entry->prev;
+        }
+        device_pm_unlock();
+        return ret;
+}
+
 static int early_resume_init(void)
 {
         hash_value_early_read = read_magic_time();