From 4dbe191c046e71d6ea1ba85365ecb33961b07c4f Mon Sep 17 00:00:00 2001 From: Saravana Kannan Date: Fri, 20 Mar 2020 21:54:48 -0700 Subject: [PATCH] driver core: Add device links from fwnode only for the primary device Sometimes, more than one (generally two) device can point to the same fwnode. However, only one device is set as the fwnode's device (fwnode->dev) and can be looked up from the fwnode. Typically, only one of these devices actually have a driver and actually probe. If we create device links for all these devices, then the suppliers' of these devices (with the same fwnode) will never get a sync_state() call because one of their consumer devices will never probe (because they don't have a driver). So, create device links only for the device that is considered as the fwnode's device. One such example of this is the PCI bridge platform_device and the corresponding pci_bus device. Both these devices will have the same fwnode. It's the platform_device that is registered first and is set as the fwnode's device. Also the platform_device is the one that actually probes. Without this patch none of the suppliers of a PCI bridge platform_device would get a sync_state() callback. Cc: Bjorn Helgaas Cc: linux-pci@vger.kernel.org Reviewed-by: Rafael J. Wysocki Signed-off-by: Saravana Kannan Link: https://lore.kernel.org/r/20200321045448.15192-1-saravanak@google.com Signed-off-by: Greg Kroah-Hartman --- drivers/base/core.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/base/core.c b/drivers/base/core.c index fc6a609..5e3cc16 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -2404,6 +2404,7 @@ int device_add(struct device *dev) struct class_interface *class_intf; int error = -EINVAL, fw_ret; struct kobject *glue_dir = NULL; + bool is_fwnode_dev = false; dev = get_device(dev); if (!dev) @@ -2501,8 +2502,10 @@ int device_add(struct device *dev) kobject_uevent(&dev->kobj, KOBJ_ADD); - if (dev->fwnode && !dev->fwnode->dev) + if (dev->fwnode && !dev->fwnode->dev) { dev->fwnode->dev = dev; + is_fwnode_dev = true; + } /* * Check if any of the other devices (consumers) have been waiting for @@ -2518,7 +2521,8 @@ int device_add(struct device *dev) */ device_link_add_missing_supplier_links(); - if (fw_devlink_flags && fwnode_has_op(dev->fwnode, add_links)) { + if (fw_devlink_flags && is_fwnode_dev && + fwnode_has_op(dev->fwnode, add_links)) { fw_ret = fwnode_call_int_op(dev->fwnode, add_links, dev); if (fw_ret == -ENODEV) device_link_wait_for_mandatory_supplier(dev); -- 2.7.4