gpu: host1x: Detach driver on unregister

From: Thierry Reding <[email protected]>

Currently when a host1x device driver is unregistered, it is not detached from the host1x controller, which means that the device will stay around and when the driver is registered again, it may bind to the old, stale device rather than the new one that was created from scratch upon driver registration. This in turn can cause various weird crashes within the driver core because it is confronted with a device that was already deleted.

Fix this by detaching the driver from the host1x controller when it is unregistered. This ensures that the deleted device also is no longer present in the device list that drivers will bind to.

---
 drivers/gpu/host1x/bus.c | 9 +++++++++
 1 file changed, 9 insertions(+)

index 6a995db51d6d..e201f62d62c0 100644
@@ -686,8 +686,17 @@ EXPORT_SYMBOL(host1x_driver_register_full);
  */
 void host1x_driver_unregister(struct host1x_driver *driver)
 {
+	struct host1x *host1x;
+
 	driver_unregister(&driver->driver);
 
+	mutex_lock(&devices_lock);
+
+	list_for_each_entry(host1x, &devices, list)
+		host1x_detach_driver(host1x, driver);
+
+	mutex_unlock(&devices_lock);
+
 	mutex_lock(&drivers_lock);
 	list_del_init(&driver->list);
 	mutex_unlock(&drivers_lock);

2.24.1