For debugging purposes it may be useful to know what are the devices whose
probe function was deferred. Add a debugfs entry showing that information.
$ cat /sys/kernel/debug/deferred_devices
48070000.i2c:twl@48:bci
musb-hdrc.0.auto
omapdrm.0
Signed-off-by: Javier Martinez Canillas <javi...@redhat.com>
---
drivers/base/dd.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 45 insertions(+)
diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index 1435d7281c6..98a3ab4a852 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -224,6 +224,43 @@ void device_unblock_probing(void)
driver_deferred_probe_trigger();
}
+#if IS_ENABLED(CONFIG_DEBUG_FS)
+#include <linux/debugfs.h>
+
+static struct dentry *deferred_devices;
+
+/*
+ * deferred_devs_show() - Show the devices in the deferred probe pending list.
+ */
+static int deferred_devs_show(struct seq_file *s, void *data)
+{
+ struct device_private *curr;
+ int ret = 0;
+
+ mutex_lock(&deferred_probe_mutex);
+
+ list_for_each_entry(curr, &deferred_probe_pending_list, deferred_probe)
+ seq_printf(s, "%s\n", dev_name(curr->device));
+
+ mutex_unlock(&deferred_probe_mutex);
+
+ return ret;
+}
+
+static int deferred_devs_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, deferred_devs_show, inode->i_private);
+}
+
+static const struct file_operations deferred_devs_fops = {
+ .owner = THIS_MODULE,
+ .open = deferred_devs_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+};
+#endif /* IS_ENABLED(CONFIG_DEBUG_FS) */
+
/**
* deferred_probe_initcall() - Enable probing of deferred devices
*
@@ -233,6 +270,14 @@ void device_unblock_probing(void)
*/
static int deferred_probe_initcall(void)
{
+ if (IS_ENABLED(CONFIG_DEBUG_FS)) {
+ deferred_devices = debugfs_create_file("deferred_devices",
+ 0444, NULL, NULL,
+ &deferred_devs_fops);
+ if (!deferred_devices)
+ return -ENOMEM;
+ }
+
driver_deferred_probe_enable = true;
driver_deferred_probe_trigger();
/* Sort as many dependencies as possible before exiting initcalls */
--
2.17.1
