driver core: Add fw_devlink.sync_state command line param

When all devices that could probe have finished probing (based on
deferred_probe_timeout configuration or late_initcall() when
!CONFIG_MODULES), this parameter controls what to do with devices that
haven't yet received their sync_state() calls.

fw_devlink.sync_state=strict is the default and the driver core will
continue waiting on all consumers of a device to probe successfully
before sync_state() is called for the device. This is the default
behavior since calling sync_state() on a device when all its consumers
haven't probed could make some systems unusable/unstable. When this
option is selected, we also print the list of devices that haven't had
sync_state() called on them by the time all devices the could probe have
finished probing.

fw_devlink.sync_state=timeout will cause the driver core to give up
waiting on consumers and call sync_state() on any devices that haven't
yet received their sync_state() calls. This option is provided for
systems that won't become unusable/unstable as they might be able to
save power (depends on state of hardware before kernel starts) if all
devices get their sync_state().

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20230304005355.746421-2-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index 8def2ba08a82..84f07e0050dd 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -315,6 +315,8 @@ static void deferred_probe_timeout_work_func(struct work_struct *work)
 	list_for_each_entry(p, &deferred_probe_pending_list, deferred_probe)
 		dev_info(p->device, "deferred probe pending\n");
 	mutex_unlock(&deferred_probe_mutex);
+
+	fw_devlink_probing_done();
 }
 static DECLARE_DELAYED_WORK(deferred_probe_timeout_work, deferred_probe_timeout_work_func);
 
@@ -364,6 +366,10 @@ static int deferred_probe_initcall(void)
 		schedule_delayed_work(&deferred_probe_timeout_work,
 			driver_deferred_probe_timeout * HZ);
 	}
+
+	if (!IS_ENABLED(CONFIG_MODULES))
+		fw_devlink_probing_done();
+
 	return 0;
 }
 late_initcall(deferred_probe_initcall);