soundwire: bus: fix race condition with initialization_complete signaling (a90def06) · Commits · 戴 / test

Waiting for the enumeration to be complete may not be enough for a Slave driver, there is a possible race condition between resume operations and initializations handled in an interrupt thread, which can results in settings not being fully restored after system or pm_runtime resume. This patch builds on the changes added for enumeration_complete, init_completion() is called when the Slave device becomes UNATTACHED, as done with enumeration_complete. The difference with the enumeration_complete case is that complete() is signaled after the Slave device is fully initialized after the .update_status() callback is called. A Slave device driver can decide to wait on either of the two complete() cases, depending on its initialization code and requirements. Signed-off-by:

Rander Wang <rander.wang@linux.intel.com> Signed-off-by:

Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com> Link: https://lore.kernel.org/r/20200115000844.14695-4-pierre-louis.bossart@linux.intel.com Signed-off-by:

Vinod Koul <vkoul@kernel.org>

drivers/soundwire/bus.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -621,6 +621,7 @@ static void sdw_modify_slave_status(struct sdw_slave *slave,
		__func__, slave->dev_num);

		init_completion(&slave->enumeration_complete);
		init_completion(&slave->initialization_complete);

		} else if ((status == SDW_SLAVE_ATTACHED) &&
		(slave->status == SDW_SLAVE_UNATTACHED)) {
		@@ -1025,6 +1026,7 @@ int sdw_handle_slave_status(struct sdw_bus *bus,
		{
		enum sdw_slave_status prev_status;
		struct sdw_slave *slave;
		bool attached_initializing;
		int i, ret = 0;

		/* first check if any Slaves fell off the bus */
		@@ -1070,6 +1072,8 @@ int sdw_handle_slave_status(struct sdw_bus *bus,
		if (!slave)
		continue;

		attached_initializing = false;

		switch (status[i]) {
		case SDW_SLAVE_UNATTACHED:
		if (slave->status == SDW_SLAVE_UNATTACHED)
		@@ -1096,6 +1100,8 @@ int sdw_handle_slave_status(struct sdw_bus *bus,
		if (prev_status == SDW_SLAVE_ALERT)
		break;

		attached_initializing = true;

		ret = sdw_initialize_slave(slave);
		if (ret)
		dev_err(bus->dev,
		@@ -1114,6 +1120,8 @@ int sdw_handle_slave_status(struct sdw_bus *bus,
		if (ret)
		dev_err(slave->bus->dev,
		"Update Slave status failed:%d\n", ret);
		if (attached_initializing)
		complete(&slave->initialization_complete);
		}

		return ret;

drivers/soundwire/slave.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -47,6 +47,7 @@ static int sdw_slave_add(struct sdw_bus *bus,
		slave->bus = bus;
		slave->status = SDW_SLAVE_UNATTACHED;
		init_completion(&slave->enumeration_complete);
		init_completion(&slave->initialization_complete);
		slave->dev_num = 0;
		init_completion(&slave->probe_complete);
		slave->probed = false;

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