From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
To: alsa-devel@alsa-project.org
Cc: linux-kernel@vger.kernel.org, tiwai@suse.de, broonie@kernel.org,
vkoul@kernel.org, gregkh@linuxfoundation.org, jank@cadence.com,
srinivas.kandagatla@linaro.org, slawomir.blauciak@intel.com,
Bard liao <yung-chuan.liao@linux.intel.com>,
Rander Wang <rander.wang@linux.intel.com>,
Ranjani Sridharan <ranjani.sridharan@linux.intel.com>,
Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>,
Sanyog Kale <sanyog.r.kale@intel.com>
Subject: [PATCH 03/10] soundwire: bus: fix race condition with initialization_complete signaling
Date: Tue, 14 Jan 2020 18:08:37 -0600 [thread overview]
Message-ID: <20200115000844.14695-4-pierre-louis.bossart@linux.intel.com> (raw)
In-Reply-To: <20200115000844.14695-1-pierre-louis.bossart@linux.intel.com>
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>
---
drivers/soundwire/bus.c | 8 ++++++++
drivers/soundwire/slave.c | 1 +
2 files changed, 9 insertions(+)
diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c
index a2267c3a1d2d..ea04cf5f5bdc 100644
--- a/drivers/soundwire/bus.c
+++ b/drivers/soundwire/bus.c
@@ -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;
diff --git a/drivers/soundwire/slave.c b/drivers/soundwire/slave.c
index e767a78066ee..aace57fae7f8 100644
--- a/drivers/soundwire/slave.c
+++ b/drivers/soundwire/slave.c
@@ -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;
--
2.20.1
next prev parent reply other threads:[~2020-01-15 0:09 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-15 0:08 [PATCH 00/10] soundwire: bus: fix race conditions, add suspend-resume Pierre-Louis Bossart
2020-01-15 0:08 ` [PATCH 01/10] soundwire: bus: fix race condition with probe_complete signaling Pierre-Louis Bossart
2020-01-15 0:08 ` [PATCH 02/10] soundwire: bus: fix race condition with enumeration_complete signaling Pierre-Louis Bossart
2020-01-15 0:08 ` Pierre-Louis Bossart [this message]
2020-01-15 0:08 ` [PATCH 04/10] soundwire: bus: add PM/no-PM versions of read/write functions Pierre-Louis Bossart
2020-01-15 0:08 ` [PATCH 05/10] soundwire: bus: write Slave Device Number without runtime_pm Pierre-Louis Bossart
2020-01-15 0:08 ` [PATCH 06/10] soundwire: bus: add helper to clear Slave status to UNATTACHED Pierre-Louis Bossart
2020-01-15 0:08 ` [PATCH 07/10] soundwire: bus: disable pm_runtime in sdw_slave_delete Pierre-Louis Bossart
2020-01-15 0:08 ` [PATCH 08/10] soundwire: bus: fix io error when processing alert event Pierre-Louis Bossart
2020-01-15 0:08 ` [PATCH 09/10] soundwire: bus: add clock stop helpers Pierre-Louis Bossart
2020-01-15 0:08 ` [PATCH 10/10] soundwire: bus: don't treat CMD_IGNORED as error on ClockStop Pierre-Louis Bossart
2020-02-10 14:30 ` [alsa-devel] [PATCH 00/10] soundwire: bus: fix race conditions, add suspend-resume Pierre-Louis Bossart
2020-02-25 10:27 ` Vinod Koul
2020-02-25 15:23 ` Pierre-Louis Bossart
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