[PATCH 1/2] soundwire: intel_auxdevice: enable pm_runtime earlier on startup

[Bard Liao]

From: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>

As soon as the bus starts, physical peripheral devices may report as
ATTACHED and set their status with pm_runtime_set_active() in their
update_status()/io_init().

This is problematic with the existing code, since the parent
pm_runtime status is changed to "active" after starting the bus. This
creates a time window where the pm_runtime framework can report an
issue, e.g.

"rt711 sdw:0:025d:0711:00: runtime PM trying to activate child device
sdw:0:025d:0711:00 but parent (sdw-master-0) is not active"

This patch enables runtime_pm earlier to make sure the auxiliary
device is pm_runtime active after powering-up, but before starting the
bus.

This problem was exposed by recent changes in the timing of the bus
reset, but was present in this driver since we introduced pm_runtime
support.

Closes: https://github.com/thesofproject/linux/issues/4328
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@xxxxxxxxxxxxxxx>
Reviewed-by: Rander Wang <rander.wang@xxxxxxxxx>
Signed-off-by: Bard Liao <yung-chuan.liao@xxxxxxxxxxxxxxx>
---
 drivers/soundwire/intel_auxdevice.c | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/drivers/soundwire/intel_auxdevice.c b/drivers/soundwire/intel_auxdevice.c
index 0daa6ca9a224..f51c776eeeff 100644
--- a/drivers/soundwire/intel_auxdevice.c
+++ b/drivers/soundwire/intel_auxdevice.c
@@ -248,13 +248,6 @@ int intel_link_startup(struct auxiliary_device *auxdev)
 
 	sdw_intel_debugfs_init(sdw);
 
-	/* start bus */
-	ret = sdw_intel_start_bus(sdw);
-	if (ret) {
-		dev_err(dev, "bus start failed: %d\n", ret);
-		goto err_power_up;
-	}
-
 	/* Enable runtime PM */
 	if (!(link_flags & SDW_INTEL_MASTER_DISABLE_PM_RUNTIME)) {
 		pm_runtime_set_autosuspend_delay(dev,
@@ -266,6 +259,13 @@ int intel_link_startup(struct auxiliary_device *auxdev)
 		pm_runtime_enable(dev);
 	}
 
+	/* start bus */
+	ret = sdw_intel_start_bus(sdw);
+	if (ret) {
+		dev_err(dev, "bus start failed: %d\n", ret);
+		goto err_pm_runtime;
+	}
+
 	clock_stop_quirks = sdw->link_res->clock_stop_quirks;
 	if (clock_stop_quirks & SDW_INTEL_CLK_STOP_NOT_ALLOWED) {
 		/*
@@ -293,12 +293,17 @@ int intel_link_startup(struct auxiliary_device *auxdev)
 	 * with a delay. A more complete solution would require the
 	 * definition of Master properties.
 	 */
-	if (!(link_flags & SDW_INTEL_MASTER_DISABLE_PM_RUNTIME_IDLE))
+	if (!(link_flags & SDW_INTEL_MASTER_DISABLE_PM_RUNTIME_IDLE)) {
+		pm_runtime_mark_last_busy(dev);
 		pm_runtime_idle(dev);
+	}
 
 	sdw->startup_done = true;
 	return 0;
 
+err_pm_runtime:
+	if (!(link_flags & SDW_INTEL_MASTER_DISABLE_PM_RUNTIME))
+		pm_runtime_disable(dev);
 err_power_up:
 	sdw_intel_link_power_down(sdw);
 err_init:
-- 
2.25.1