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* [PATCH 0/7] soundwire/regmap: use _no_pm routines
@ 2020-12-02 20:46 Bard Liao
  2020-12-02 20:46 ` [PATCH 1/7] soundwire: bus: use sdw_update_no_pm when initializing a device Bard Liao
                   ` (6 more replies)
  0 siblings, 7 replies; 19+ messages in thread
From: Bard Liao @ 2020-12-02 20:46 UTC (permalink / raw)
  To: alsa-devel, vkoul
  Cc: vinod.koul, linux-kernel, tiwai, broonie, gregkh, jank,
	srinivas.kandagatla, rander.wang, ranjani.sridharan, hui.wang,
	pierre-louis.bossart, sanyog.r.kale, bard.liao

When a Slave device is resumed, it may resume the bus and restart the
enumeration. And Slave drivers will wait for initialization_complete
complete in their resume function, however initialization_complete will
complete after sdw_update_slave_status function is finished and codec
driver usually call some IO functions in the update_status callback
function.
It will become a deadlock if we use regular read/write routines during
the resuming process.

This series touches both soundwire and regmap trees.
commit fb5103f9d6ce ("regmap/SoundWire: sdw: add support for SoundWire 1.2 MBQ")
is needed for soundwire tree to complie.
On the other hands,
commit 6e06a85556f9 ("soundwire: bus: add comments to explain interrupt loop filter")
to
commit 47b8520997a8 ("soundwire: bus: only clear valid DPN interrupts")
are needed for regmap tree.

Bard Liao (2):
  soundwire/regmap: use _no_pm functions in regmap_read/write
  regmap: sdw: use no_pm routines for SoundWire 1.2 MBQ

Pierre-Louis Bossart (5):
  soundwire: bus: use sdw_update_no_pm when initializing a device
  soundwire: bus: use sdw_write_no_pm when setting the bus scale
    registers
  soundwire: bus: use no_pm IO routines for all interrupt handling
  soundwire: bus: fix confusion on device used by pm_runtime
  soundwire: bus: clarify dev_err/dbg device references

 drivers/base/regmap/regmap-sdw-mbq.c |  10 +-
 drivers/base/regmap/regmap-sdw.c     |   4 +-
 drivers/soundwire/bus.c              | 135 +++++++++++++++------------
 include/linux/soundwire/sdw.h        |   2 +
 4 files changed, 85 insertions(+), 66 deletions(-)

-- 
2.17.1


^ permalink raw reply	[flat|nested] 19+ messages in thread

* [PATCH 1/7] soundwire: bus: use sdw_update_no_pm when initializing a device
  2020-12-02 20:46 [PATCH 0/7] soundwire/regmap: use _no_pm routines Bard Liao
@ 2020-12-02 20:46 ` Bard Liao
  2020-12-05  7:45   ` Vinod Koul
  2020-12-02 20:46 ` [PATCH 2/7] soundwire: bus: use sdw_write_no_pm when setting the bus scale registers Bard Liao
                   ` (5 subsequent siblings)
  6 siblings, 1 reply; 19+ messages in thread
From: Bard Liao @ 2020-12-02 20:46 UTC (permalink / raw)
  To: alsa-devel, vkoul
  Cc: vinod.koul, linux-kernel, tiwai, broonie, gregkh, jank,
	srinivas.kandagatla, rander.wang, ranjani.sridharan, hui.wang,
	pierre-louis.bossart, sanyog.r.kale, bard.liao

From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>

When a Slave device is resumed, it may resume the bus and restart the
enumeration. During that process, we absolutely don't want to call
regular read/write routines which will wait for the resume to
complete, otherwise a deadlock occurs.

Fixes: 60ee9be25571 ('soundwire: bus: add PM/no-PM versions of read/write functions')
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@linux.intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
---
 drivers/soundwire/bus.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c
index d1e8c3a54976..60c42508c6c6 100644
--- a/drivers/soundwire/bus.c
+++ b/drivers/soundwire/bus.c
@@ -489,6 +489,18 @@ sdw_read_no_pm(struct sdw_slave *slave, u32 addr)
 		return buf;
 }
 
+static int sdw_update_no_pm(struct sdw_slave *slave, u32 addr, u8 mask, u8 val)
+{
+	int tmp;
+
+	tmp = sdw_read_no_pm(slave, addr);
+	if (tmp < 0)
+		return tmp;
+
+	tmp = (tmp & ~mask) | val;
+	return sdw_write_no_pm(slave, addr, tmp);
+}
+
 /**
  * sdw_nread() - Read "n" contiguous SDW Slave registers
  * @slave: SDW Slave
@@ -1256,7 +1268,7 @@ static int sdw_initialize_slave(struct sdw_slave *slave)
 	val = slave->prop.scp_int1_mask;
 
 	/* Enable SCP interrupts */
-	ret = sdw_update(slave, SDW_SCP_INTMASK1, val, val);
+	ret = sdw_update_no_pm(slave, SDW_SCP_INTMASK1, val, val);
 	if (ret < 0) {
 		dev_err(slave->bus->dev,
 			"SDW_SCP_INTMASK1 write failed:%d\n", ret);
@@ -1271,7 +1283,7 @@ static int sdw_initialize_slave(struct sdw_slave *slave)
 	val = prop->dp0_prop->imp_def_interrupts;
 	val |= SDW_DP0_INT_PORT_READY | SDW_DP0_INT_BRA_FAILURE;
 
-	ret = sdw_update(slave, SDW_DP0_INTMASK, val, val);
+	ret = sdw_update_no_pm(slave, SDW_DP0_INTMASK, val, val);
 	if (ret < 0)
 		dev_err(slave->bus->dev,
 			"SDW_DP0_INTMASK read failed:%d\n", ret);
-- 
2.17.1


^ permalink raw reply	[flat|nested] 19+ messages in thread

* [PATCH 2/7] soundwire: bus: use sdw_write_no_pm when setting the bus scale registers
  2020-12-02 20:46 [PATCH 0/7] soundwire/regmap: use _no_pm routines Bard Liao
  2020-12-02 20:46 ` [PATCH 1/7] soundwire: bus: use sdw_update_no_pm when initializing a device Bard Liao
@ 2020-12-02 20:46 ` Bard Liao
  2020-12-02 20:46 ` [PATCH 3/7] soundwire: bus: use no_pm IO routines for all interrupt handling Bard Liao
                   ` (4 subsequent siblings)
  6 siblings, 0 replies; 19+ messages in thread
From: Bard Liao @ 2020-12-02 20:46 UTC (permalink / raw)
  To: alsa-devel, vkoul
  Cc: vinod.koul, linux-kernel, tiwai, broonie, gregkh, jank,
	srinivas.kandagatla, rander.wang, ranjani.sridharan, hui.wang,
	pierre-louis.bossart, sanyog.r.kale, bard.liao

From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>

When a Slave device is resumed, it may resume the bus and restart the
enumeration. During that process, we absolutely don't want to call
regular read/write routines which will wait for the resume to
complete, otherwise a deadlock occurs.

This patch fixes the same problem as the previous one, but is split to
make the life of linux-stable maintainers less painful.

Fixes: 29d158f90690 ('soundwire: bus: initialize bus clock base and scale registers')
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@linux.intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
---
 drivers/soundwire/bus.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c
index 60c42508c6c6..b1830032b052 100644
--- a/drivers/soundwire/bus.c
+++ b/drivers/soundwire/bus.c
@@ -1222,7 +1222,7 @@ static int sdw_slave_set_frequency(struct sdw_slave *slave)
 	}
 	scale_index++;
 
-	ret = sdw_write(slave, SDW_SCP_BUS_CLOCK_BASE, base);
+	ret = sdw_write_no_pm(slave, SDW_SCP_BUS_CLOCK_BASE, base);
 	if (ret < 0) {
 		dev_err(&slave->dev,
 			"SDW_SCP_BUS_CLOCK_BASE write failed:%d\n", ret);
@@ -1230,13 +1230,13 @@ static int sdw_slave_set_frequency(struct sdw_slave *slave)
 	}
 
 	/* initialize scale for both banks */
-	ret = sdw_write(slave, SDW_SCP_BUSCLOCK_SCALE_B0, scale_index);
+	ret = sdw_write_no_pm(slave, SDW_SCP_BUSCLOCK_SCALE_B0, scale_index);
 	if (ret < 0) {
 		dev_err(&slave->dev,
 			"SDW_SCP_BUSCLOCK_SCALE_B0 write failed:%d\n", ret);
 		return ret;
 	}
-	ret = sdw_write(slave, SDW_SCP_BUSCLOCK_SCALE_B1, scale_index);
+	ret = sdw_write_no_pm(slave, SDW_SCP_BUSCLOCK_SCALE_B1, scale_index);
 	if (ret < 0)
 		dev_err(&slave->dev,
 			"SDW_SCP_BUSCLOCK_SCALE_B1 write failed:%d\n", ret);
-- 
2.17.1


^ permalink raw reply	[flat|nested] 19+ messages in thread

* [PATCH 3/7] soundwire: bus: use no_pm IO routines for all interrupt handling
  2020-12-02 20:46 [PATCH 0/7] soundwire/regmap: use _no_pm routines Bard Liao
  2020-12-02 20:46 ` [PATCH 1/7] soundwire: bus: use sdw_update_no_pm when initializing a device Bard Liao
  2020-12-02 20:46 ` [PATCH 2/7] soundwire: bus: use sdw_write_no_pm when setting the bus scale registers Bard Liao
@ 2020-12-02 20:46 ` Bard Liao
  2020-12-02 20:46 ` [PATCH 4/7] soundwire/regmap: use _no_pm functions in regmap_read/write Bard Liao
                   ` (3 subsequent siblings)
  6 siblings, 0 replies; 19+ messages in thread
From: Bard Liao @ 2020-12-02 20:46 UTC (permalink / raw)
  To: alsa-devel, vkoul
  Cc: vinod.koul, linux-kernel, tiwai, broonie, gregkh, jank,
	srinivas.kandagatla, rander.wang, ranjani.sridharan, hui.wang,
	pierre-louis.bossart, sanyog.r.kale, bard.liao

From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>

There is no need to play with pm_runtime reference counts, if needed
the codec drivers are already explicitly resumed.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@linux.intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
---
 drivers/soundwire/bus.c | 26 +++++++++++++-------------
 1 file changed, 13 insertions(+), 13 deletions(-)

diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c
index b1830032b052..86c339d77a39 100644
--- a/drivers/soundwire/bus.c
+++ b/drivers/soundwire/bus.c
@@ -1295,7 +1295,7 @@ static int sdw_handle_dp0_interrupt(struct sdw_slave *slave, u8 *slave_status)
 	u8 clear, impl_int_mask;
 	int status, status2, ret, count = 0;
 
-	status = sdw_read(slave, SDW_DP0_INT);
+	status = sdw_read_no_pm(slave, SDW_DP0_INT);
 	if (status < 0) {
 		dev_err(slave->bus->dev,
 			"SDW_DP0_INT read failed:%d\n", status);
@@ -1334,7 +1334,7 @@ static int sdw_handle_dp0_interrupt(struct sdw_slave *slave, u8 *slave_status)
 		}
 
 		/* clear the interrupts but don't touch reserved and SDCA_CASCADE fields */
-		ret = sdw_write(slave, SDW_DP0_INT, clear);
+		ret = sdw_write_no_pm(slave, SDW_DP0_INT, clear);
 		if (ret < 0) {
 			dev_err(slave->bus->dev,
 				"SDW_DP0_INT write failed:%d\n", ret);
@@ -1342,7 +1342,7 @@ static int sdw_handle_dp0_interrupt(struct sdw_slave *slave, u8 *slave_status)
 		}
 
 		/* Read DP0 interrupt again */
-		status2 = sdw_read(slave, SDW_DP0_INT);
+		status2 = sdw_read_no_pm(slave, SDW_DP0_INT);
 		if (status2 < 0) {
 			dev_err(slave->bus->dev,
 				"SDW_DP0_INT read failed:%d\n", status2);
@@ -1373,7 +1373,7 @@ static int sdw_handle_port_interrupt(struct sdw_slave *slave,
 		return sdw_handle_dp0_interrupt(slave, slave_status);
 
 	addr = SDW_DPN_INT(port);
-	status = sdw_read(slave, addr);
+	status = sdw_read_no_pm(slave, addr);
 	if (status < 0) {
 		dev_err(slave->bus->dev,
 			"SDW_DPN_INT read failed:%d\n", status);
@@ -1407,7 +1407,7 @@ static int sdw_handle_port_interrupt(struct sdw_slave *slave,
 		}
 
 		/* clear the interrupt but don't touch reserved fields */
-		ret = sdw_write(slave, addr, clear);
+		ret = sdw_write_no_pm(slave, addr, clear);
 		if (ret < 0) {
 			dev_err(slave->bus->dev,
 				"SDW_DPN_INT write failed:%d\n", ret);
@@ -1415,7 +1415,7 @@ static int sdw_handle_port_interrupt(struct sdw_slave *slave,
 		}
 
 		/* Read DPN interrupt again */
-		status2 = sdw_read(slave, addr);
+		status2 = sdw_read_no_pm(slave, addr);
 		if (status2 < 0) {
 			dev_err(slave->bus->dev,
 				"SDW_DPN_INT read failed:%d\n", status2);
@@ -1457,7 +1457,7 @@ static int sdw_handle_slave_alerts(struct sdw_slave *slave)
 	}
 
 	/* Read Intstat 1, Intstat 2 and Intstat 3 registers */
-	ret = sdw_read(slave, SDW_SCP_INT1);
+	ret = sdw_read_no_pm(slave, SDW_SCP_INT1);
 	if (ret < 0) {
 		dev_err(slave->bus->dev,
 			"SDW_SCP_INT1 read failed:%d\n", ret);
@@ -1465,7 +1465,7 @@ static int sdw_handle_slave_alerts(struct sdw_slave *slave)
 	}
 	buf = ret;
 
-	ret = sdw_nread(slave, SDW_SCP_INTSTAT2, 2, buf2);
+	ret = sdw_nread_no_pm(slave, SDW_SCP_INTSTAT2, 2, buf2);
 	if (ret < 0) {
 		dev_err(slave->bus->dev,
 			"SDW_SCP_INT2/3 read failed:%d\n", ret);
@@ -1473,7 +1473,7 @@ static int sdw_handle_slave_alerts(struct sdw_slave *slave)
 	}
 
 	if (slave->prop.is_sdca) {
-		ret = sdw_read(slave, SDW_DP0_INT);
+		ret = sdw_read_no_pm(slave, SDW_DP0_INT);
 		if (ret < 0) {
 			dev_err(slave->bus->dev,
 				"SDW_DP0_INT read failed:%d\n", ret);
@@ -1570,7 +1570,7 @@ static int sdw_handle_slave_alerts(struct sdw_slave *slave)
 		}
 
 		/* Ack interrupt */
-		ret = sdw_write(slave, SDW_SCP_INT1, clear);
+		ret = sdw_write_no_pm(slave, SDW_SCP_INT1, clear);
 		if (ret < 0) {
 			dev_err(slave->bus->dev,
 				"SDW_SCP_INT1 write failed:%d\n", ret);
@@ -1584,7 +1584,7 @@ static int sdw_handle_slave_alerts(struct sdw_slave *slave)
 		 * Read status again to ensure no new interrupts arrived
 		 * while servicing interrupts.
 		 */
-		ret = sdw_read(slave, SDW_SCP_INT1);
+		ret = sdw_read_no_pm(slave, SDW_SCP_INT1);
 		if (ret < 0) {
 			dev_err(slave->bus->dev,
 				"SDW_SCP_INT1 read failed:%d\n", ret);
@@ -1592,7 +1592,7 @@ static int sdw_handle_slave_alerts(struct sdw_slave *slave)
 		}
 		_buf = ret;
 
-		ret = sdw_nread(slave, SDW_SCP_INTSTAT2, 2, _buf2);
+		ret = sdw_nread_no_pm(slave, SDW_SCP_INTSTAT2, 2, _buf2);
 		if (ret < 0) {
 			dev_err(slave->bus->dev,
 				"SDW_SCP_INT2/3 read failed:%d\n", ret);
@@ -1600,7 +1600,7 @@ static int sdw_handle_slave_alerts(struct sdw_slave *slave)
 		}
 
 		if (slave->prop.is_sdca) {
-			ret = sdw_read(slave, SDW_DP0_INT);
+			ret = sdw_read_no_pm(slave, SDW_DP0_INT);
 			if (ret < 0) {
 				dev_err(slave->bus->dev,
 					"SDW_DP0_INT read failed:%d\n", ret);
-- 
2.17.1


^ permalink raw reply	[flat|nested] 19+ messages in thread

* [PATCH 4/7] soundwire/regmap: use _no_pm functions in regmap_read/write
  2020-12-02 20:46 [PATCH 0/7] soundwire/regmap: use _no_pm routines Bard Liao
                   ` (2 preceding siblings ...)
  2020-12-02 20:46 ` [PATCH 3/7] soundwire: bus: use no_pm IO routines for all interrupt handling Bard Liao
@ 2020-12-02 20:46 ` Bard Liao
  2020-12-05  7:45   ` Vinod Koul
  2020-12-02 20:46 ` [PATCH 5/7] regmap: sdw: use no_pm routines for SoundWire 1.2 MBQ Bard Liao
                   ` (2 subsequent siblings)
  6 siblings, 1 reply; 19+ messages in thread
From: Bard Liao @ 2020-12-02 20:46 UTC (permalink / raw)
  To: alsa-devel, vkoul
  Cc: vinod.koul, linux-kernel, tiwai, broonie, gregkh, jank,
	srinivas.kandagatla, rander.wang, ranjani.sridharan, hui.wang,
	pierre-louis.bossart, sanyog.r.kale, bard.liao

sdw_update_slave_status will be invoked when a codec is attached,
and the codec driver will initialize the codec with regmap functions
while the codec device is pm_runtime suspended.

regmap routines currently rely on regular SoundWire IO functions,
which will call pm_runtime_get_sync()/put_autosuspend.

This causes a deadlock where the resume routine waits for an
initialization complete signal that while the initialization complete
can only be reached when the resume completes.

The only solution if we allow regmap functions to be used in resume
operations as well as during codec initialization is to use _no_pm
routines. The duty of making sure the bus is operational needs to be
handled above the regmap level.

Fixes: 7c22ce6e21840 ('regmap: Add SoundWire bus support')
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@linux.intel.com>
---
 drivers/base/regmap/regmap-sdw.c | 4 ++--
 drivers/soundwire/bus.c          | 6 ++++--
 include/linux/soundwire/sdw.h    | 2 ++
 3 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/base/regmap/regmap-sdw.c b/drivers/base/regmap/regmap-sdw.c
index c92d614b4943..4b8d2d010cab 100644
--- a/drivers/base/regmap/regmap-sdw.c
+++ b/drivers/base/regmap/regmap-sdw.c
@@ -11,7 +11,7 @@ static int regmap_sdw_write(void *context, unsigned int reg, unsigned int val)
 	struct device *dev = context;
 	struct sdw_slave *slave = dev_to_sdw_dev(dev);
 
-	return sdw_write(slave, reg, val);
+	return sdw_write_no_pm(slave, reg, val);
 }
 
 static int regmap_sdw_read(void *context, unsigned int reg, unsigned int *val)
@@ -20,7 +20,7 @@ static int regmap_sdw_read(void *context, unsigned int reg, unsigned int *val)
 	struct sdw_slave *slave = dev_to_sdw_dev(dev);
 	int read;
 
-	read = sdw_read(slave, reg);
+	read = sdw_read_no_pm(slave, reg);
 	if (read < 0)
 		return read;
 
diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c
index 86c339d77a39..c5ea59673dee 100644
--- a/drivers/soundwire/bus.c
+++ b/drivers/soundwire/bus.c
@@ -405,10 +405,11 @@ sdw_nwrite_no_pm(struct sdw_slave *slave, u32 addr, size_t count, u8 *val)
 	return sdw_transfer(slave->bus, &msg);
 }
 
-static int sdw_write_no_pm(struct sdw_slave *slave, u32 addr, u8 value)
+int sdw_write_no_pm(struct sdw_slave *slave, u32 addr, u8 value)
 {
 	return sdw_nwrite_no_pm(slave, addr, 1, &value);
 }
+EXPORT_SYMBOL(sdw_write_no_pm);
 
 static int
 sdw_bread_no_pm(struct sdw_bus *bus, u16 dev_num, u32 addr)
@@ -476,7 +477,7 @@ int sdw_bwrite_no_pm_unlocked(struct sdw_bus *bus, u16 dev_num, u32 addr, u8 val
 }
 EXPORT_SYMBOL(sdw_bwrite_no_pm_unlocked);
 
-static int
+int
 sdw_read_no_pm(struct sdw_slave *slave, u32 addr)
 {
 	u8 buf;
@@ -488,6 +489,7 @@ sdw_read_no_pm(struct sdw_slave *slave, u32 addr)
 	else
 		return buf;
 }
+EXPORT_SYMBOL(sdw_read_no_pm);
 
 static int sdw_update_no_pm(struct sdw_slave *slave, u32 addr, u8 mask, u8 val)
 {
diff --git a/include/linux/soundwire/sdw.h b/include/linux/soundwire/sdw.h
index f0b01b728640..d08039d65825 100644
--- a/include/linux/soundwire/sdw.h
+++ b/include/linux/soundwire/sdw.h
@@ -1005,6 +1005,8 @@ int sdw_bus_exit_clk_stop(struct sdw_bus *bus);
 
 int sdw_read(struct sdw_slave *slave, u32 addr);
 int sdw_write(struct sdw_slave *slave, u32 addr, u8 value);
+int sdw_write_no_pm(struct sdw_slave *slave, u32 addr, u8 value);
+int sdw_read_no_pm(struct sdw_slave *slave, u32 addr);
 int sdw_nread(struct sdw_slave *slave, u32 addr, size_t count, u8 *val);
 int sdw_nwrite(struct sdw_slave *slave, u32 addr, size_t count, u8 *val);
 
-- 
2.17.1


^ permalink raw reply	[flat|nested] 19+ messages in thread

* [PATCH 5/7] regmap: sdw: use no_pm routines for SoundWire 1.2 MBQ
  2020-12-02 20:46 [PATCH 0/7] soundwire/regmap: use _no_pm routines Bard Liao
                   ` (3 preceding siblings ...)
  2020-12-02 20:46 ` [PATCH 4/7] soundwire/regmap: use _no_pm functions in regmap_read/write Bard Liao
@ 2020-12-02 20:46 ` Bard Liao
  2020-12-05  7:46   ` Vinod Koul
  2020-12-02 20:46 ` [PATCH 6/7] soundwire: bus: fix confusion on device used by pm_runtime Bard Liao
  2020-12-02 20:46 ` [PATCH 7/7] soundwire: bus: clarify dev_err/dbg device references Bard Liao
  6 siblings, 1 reply; 19+ messages in thread
From: Bard Liao @ 2020-12-02 20:46 UTC (permalink / raw)
  To: alsa-devel, vkoul
  Cc: vinod.koul, linux-kernel, tiwai, broonie, gregkh, jank,
	srinivas.kandagatla, rander.wang, ranjani.sridharan, hui.wang,
	pierre-louis.bossart, sanyog.r.kale, bard.liao

Use no_pm versions for write and read.

Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@linux.intel.com>
---
 drivers/base/regmap/regmap-sdw-mbq.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/base/regmap/regmap-sdw-mbq.c b/drivers/base/regmap/regmap-sdw-mbq.c
index 8ce30650b97c..fe3ac26b66ad 100644
--- a/drivers/base/regmap/regmap-sdw-mbq.c
+++ b/drivers/base/regmap/regmap-sdw-mbq.c
@@ -15,11 +15,11 @@ static int regmap_sdw_mbq_write(void *context, unsigned int reg, unsigned int va
 	struct sdw_slave *slave = dev_to_sdw_dev(dev);
 	int ret;
 
-	ret = sdw_write(slave, SDW_SDCA_MBQ_CTL(reg), (val >> 8) & 0xff);
+	ret = sdw_write_no_pm(slave, SDW_SDCA_MBQ_CTL(reg), (val >> 8) & 0xff);
 	if (ret < 0)
 		return ret;
 
-	return sdw_write(slave, reg, val & 0xff);
+	return sdw_write_no_pm(slave, reg, val & 0xff);
 }
 
 static int regmap_sdw_mbq_read(void *context, unsigned int reg, unsigned int *val)
@@ -29,11 +29,11 @@ static int regmap_sdw_mbq_read(void *context, unsigned int reg, unsigned int *va
 	int read0;
 	int read1;
 
-	read0 = sdw_read(slave, reg);
+	read0 = sdw_read_no_pm(slave, reg);
 	if (read0 < 0)
 		return read0;
 
-	read1 = sdw_read(slave, SDW_SDCA_MBQ_CTL(reg));
+	read1 = sdw_read_no_pm(slave, SDW_SDCA_MBQ_CTL(reg));
 	if (read1 < 0)
 		return read1;
 
@@ -98,4 +98,4 @@ struct regmap *__devm_regmap_init_sdw_mbq(struct sdw_slave *sdw,
 EXPORT_SYMBOL_GPL(__devm_regmap_init_sdw_mbq);
 
 MODULE_DESCRIPTION("Regmap SoundWire MBQ Module");
-MODULE_LICENSE("GPL v2");
+MODULE_LICENSE("GPL");
-- 
2.17.1


^ permalink raw reply	[flat|nested] 19+ messages in thread

* [PATCH 6/7] soundwire: bus: fix confusion on device used by pm_runtime
  2020-12-02 20:46 [PATCH 0/7] soundwire/regmap: use _no_pm routines Bard Liao
                   ` (4 preceding siblings ...)
  2020-12-02 20:46 ` [PATCH 5/7] regmap: sdw: use no_pm routines for SoundWire 1.2 MBQ Bard Liao
@ 2020-12-02 20:46 ` Bard Liao
  2020-12-02 20:46 ` [PATCH 7/7] soundwire: bus: clarify dev_err/dbg device references Bard Liao
  6 siblings, 0 replies; 19+ messages in thread
From: Bard Liao @ 2020-12-02 20:46 UTC (permalink / raw)
  To: alsa-devel, vkoul
  Cc: vinod.koul, linux-kernel, tiwai, broonie, gregkh, jank,
	srinivas.kandagatla, rander.wang, ranjani.sridharan, hui.wang,
	pierre-louis.bossart, sanyog.r.kale, bard.liao

From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>

Intel stress-tests routinely report IO timeouts and invalid power
management transitions. Upon further analysis, we seem to be using the
wrong devices in pm_runtime calls.

Before reading and writing registers, we first need to make sure the
Slave is fully resumed. The existing code attempts to do such that,
however because of a confusion dating from 2017 and copy/paste, we
end-up resuming the parent only instead of resuming the codec device.

This can lead to accesses to the Slave registers while the bus is
still being configured and the Slave not enumerated, and as a result
IO errors occur.

This is a classic problem, similar confusions happened for HDaudio
between bus and codec device, leading to power management issues.

Fix by using the relevant device for all uses of pm_runtime functions.

Fixes: 60ee9be255712 ('soundwire: bus: add PM/no-PM versions of read/write functions')
Fixes: aa79293517b39 ('soundwire: bus: fix io error when processing alert event')
Fixes: 9d715fa005ebc ('soundwire: Add IO transfer')
Reported-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@linux.intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
---
 drivers/soundwire/bus.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c
index c5ea59673dee..c317f41eba4e 100644
--- a/drivers/soundwire/bus.c
+++ b/drivers/soundwire/bus.c
@@ -514,16 +514,16 @@ int sdw_nread(struct sdw_slave *slave, u32 addr, size_t count, u8 *val)
 {
 	int ret;
 
-	ret = pm_runtime_get_sync(slave->bus->dev);
+	ret = pm_runtime_get_sync(&slave->dev);
 	if (ret < 0 && ret != -EACCES) {
-		pm_runtime_put_noidle(slave->bus->dev);
+		pm_runtime_put_noidle(&slave->dev);
 		return ret;
 	}
 
 	ret = sdw_nread_no_pm(slave, addr, count, val);
 
-	pm_runtime_mark_last_busy(slave->bus->dev);
-	pm_runtime_put(slave->bus->dev);
+	pm_runtime_mark_last_busy(&slave->dev);
+	pm_runtime_put(&slave->dev);
 
 	return ret;
 }
@@ -540,16 +540,16 @@ int sdw_nwrite(struct sdw_slave *slave, u32 addr, size_t count, u8 *val)
 {
 	int ret;
 
-	ret = pm_runtime_get_sync(slave->bus->dev);
+	ret = pm_runtime_get_sync(&slave->dev);
 	if (ret < 0 && ret != -EACCES) {
-		pm_runtime_put_noidle(slave->bus->dev);
+		pm_runtime_put_noidle(&slave->dev);
 		return ret;
 	}
 
 	ret = sdw_nwrite_no_pm(slave, addr, count, val);
 
-	pm_runtime_mark_last_busy(slave->bus->dev);
-	pm_runtime_put(slave->bus->dev);
+	pm_runtime_mark_last_busy(&slave->dev);
+	pm_runtime_put(&slave->dev);
 
 	return ret;
 }
@@ -1454,7 +1454,7 @@ static int sdw_handle_slave_alerts(struct sdw_slave *slave)
 	ret = pm_runtime_get_sync(&slave->dev);
 	if (ret < 0 && ret != -EACCES) {
 		dev_err(&slave->dev, "Failed to resume device: %d\n", ret);
-		pm_runtime_put_noidle(slave->bus->dev);
+		pm_runtime_put_noidle(&slave->dev);
 		return ret;
 	}
 
-- 
2.17.1


^ permalink raw reply	[flat|nested] 19+ messages in thread

* [PATCH 7/7] soundwire: bus: clarify dev_err/dbg device references
  2020-12-02 20:46 [PATCH 0/7] soundwire/regmap: use _no_pm routines Bard Liao
                   ` (5 preceding siblings ...)
  2020-12-02 20:46 ` [PATCH 6/7] soundwire: bus: fix confusion on device used by pm_runtime Bard Liao
@ 2020-12-02 20:46 ` Bard Liao
  6 siblings, 0 replies; 19+ messages in thread
From: Bard Liao @ 2020-12-02 20:46 UTC (permalink / raw)
  To: alsa-devel, vkoul
  Cc: vinod.koul, linux-kernel, tiwai, broonie, gregkh, jank,
	srinivas.kandagatla, rander.wang, ranjani.sridharan, hui.wang,
	pierre-louis.bossart, sanyog.r.kale, bard.liao

From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>

The SoundWire bus code confuses bus and Slave device levels for
dev_err/dbg logs. That's not impacting functionality but the accuracy
of kernel logs.

We should only use bus->dev for bus-level operations and handling of
Device0. For all other logs where the device number is not zero, we
should use &slave->dev to provide more precisions to the
user/integrator.

Reported-by: Rander Wang <rander.wang@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@linux.intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
---
 drivers/soundwire/bus.c | 63 +++++++++++++++++++++--------------------
 1 file changed, 33 insertions(+), 30 deletions(-)

diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c
index c317f41eba4e..7d07cacef740 100644
--- a/drivers/soundwire/bus.c
+++ b/drivers/soundwire/bus.c
@@ -637,6 +637,7 @@ static int sdw_get_device_num(struct sdw_slave *slave)
 
 static int sdw_assign_device_num(struct sdw_slave *slave)
 {
+	struct sdw_bus *bus = slave->bus;
 	int ret, dev_num;
 	bool new_device = false;
 
@@ -647,7 +648,7 @@ static int sdw_assign_device_num(struct sdw_slave *slave)
 			dev_num = sdw_get_device_num(slave);
 			mutex_unlock(&slave->bus->bus_lock);
 			if (dev_num < 0) {
-				dev_err(slave->bus->dev, "Get dev_num failed: %d\n",
+				dev_err(bus->dev, "Get dev_num failed: %d\n",
 					dev_num);
 				return dev_num;
 			}
@@ -660,7 +661,7 @@ static int sdw_assign_device_num(struct sdw_slave *slave)
 	}
 
 	if (!new_device)
-		dev_dbg(slave->bus->dev,
+		dev_dbg(bus->dev,
 			"Slave already registered, reusing dev_num:%d\n",
 			slave->dev_num);
 
@@ -670,7 +671,7 @@ static int sdw_assign_device_num(struct sdw_slave *slave)
 
 	ret = sdw_write_no_pm(slave, SDW_SCP_DEVNUMBER, dev_num);
 	if (ret < 0) {
-		dev_err(&slave->dev, "Program device_num %d failed: %d\n",
+		dev_err(bus->dev, "Program device_num %d failed: %d\n",
 			dev_num, ret);
 		return ret;
 	}
@@ -749,7 +750,7 @@ static int sdw_program_device_num(struct sdw_bus *bus)
 				 */
 				ret = sdw_assign_device_num(slave);
 				if (ret) {
-					dev_err(slave->bus->dev,
+					dev_err(bus->dev,
 						"Assign dev_num failed:%d\n",
 						ret);
 					return ret;
@@ -789,9 +790,11 @@ static int sdw_program_device_num(struct sdw_bus *bus)
 static void sdw_modify_slave_status(struct sdw_slave *slave,
 				    enum sdw_slave_status status)
 {
-	mutex_lock(&slave->bus->bus_lock);
+	struct sdw_bus *bus = slave->bus;
 
-	dev_vdbg(&slave->dev,
+	mutex_lock(&bus->bus_lock);
+
+	dev_vdbg(bus->dev,
 		 "%s: changing status slave %d status %d new status %d\n",
 		 __func__, slave->dev_num, slave->status, status);
 
@@ -812,7 +815,7 @@ static void sdw_modify_slave_status(struct sdw_slave *slave,
 		complete(&slave->enumeration_complete);
 	}
 	slave->status = status;
-	mutex_unlock(&slave->bus->bus_lock);
+	mutex_unlock(&bus->bus_lock);
 }
 
 static enum sdw_clk_stop_mode sdw_get_clk_stop_mode(struct sdw_slave *slave)
@@ -1141,7 +1144,7 @@ int sdw_configure_dpn_intr(struct sdw_slave *slave,
 
 	ret = sdw_update(slave, addr, (mask | SDW_DPN_INT_PORT_READY), val);
 	if (ret < 0)
-		dev_err(slave->bus->dev,
+		dev_err(&slave->dev,
 			"SDW_DPN_INTMASK write failed:%d\n", val);
 
 	return ret;
@@ -1272,7 +1275,7 @@ static int sdw_initialize_slave(struct sdw_slave *slave)
 	/* Enable SCP interrupts */
 	ret = sdw_update_no_pm(slave, SDW_SCP_INTMASK1, val, val);
 	if (ret < 0) {
-		dev_err(slave->bus->dev,
+		dev_err(&slave->dev,
 			"SDW_SCP_INTMASK1 write failed:%d\n", ret);
 		return ret;
 	}
@@ -1287,7 +1290,7 @@ static int sdw_initialize_slave(struct sdw_slave *slave)
 
 	ret = sdw_update_no_pm(slave, SDW_DP0_INTMASK, val, val);
 	if (ret < 0)
-		dev_err(slave->bus->dev,
+		dev_err(&slave->dev,
 			"SDW_DP0_INTMASK read failed:%d\n", ret);
 	return ret;
 }
@@ -1299,7 +1302,7 @@ static int sdw_handle_dp0_interrupt(struct sdw_slave *slave, u8 *slave_status)
 
 	status = sdw_read_no_pm(slave, SDW_DP0_INT);
 	if (status < 0) {
-		dev_err(slave->bus->dev,
+		dev_err(&slave->dev,
 			"SDW_DP0_INT read failed:%d\n", status);
 		return status;
 	}
@@ -1338,7 +1341,7 @@ static int sdw_handle_dp0_interrupt(struct sdw_slave *slave, u8 *slave_status)
 		/* clear the interrupts but don't touch reserved and SDCA_CASCADE fields */
 		ret = sdw_write_no_pm(slave, SDW_DP0_INT, clear);
 		if (ret < 0) {
-			dev_err(slave->bus->dev,
+			dev_err(&slave->dev,
 				"SDW_DP0_INT write failed:%d\n", ret);
 			return ret;
 		}
@@ -1346,7 +1349,7 @@ static int sdw_handle_dp0_interrupt(struct sdw_slave *slave, u8 *slave_status)
 		/* Read DP0 interrupt again */
 		status2 = sdw_read_no_pm(slave, SDW_DP0_INT);
 		if (status2 < 0) {
-			dev_err(slave->bus->dev,
+			dev_err(&slave->dev,
 				"SDW_DP0_INT read failed:%d\n", status2);
 			return status2;
 		}
@@ -1359,7 +1362,7 @@ static int sdw_handle_dp0_interrupt(struct sdw_slave *slave, u8 *slave_status)
 	} while ((status & SDW_DP0_INTERRUPTS) && (count < SDW_READ_INTR_CLEAR_RETRY));
 
 	if (count == SDW_READ_INTR_CLEAR_RETRY)
-		dev_warn(slave->bus->dev, "Reached MAX_RETRY on DP0 read\n");
+		dev_warn(&slave->dev, "Reached MAX_RETRY on DP0 read\n");
 
 	return ret;
 }
@@ -1377,7 +1380,7 @@ static int sdw_handle_port_interrupt(struct sdw_slave *slave,
 	addr = SDW_DPN_INT(port);
 	status = sdw_read_no_pm(slave, addr);
 	if (status < 0) {
-		dev_err(slave->bus->dev,
+		dev_err(&slave->dev,
 			"SDW_DPN_INT read failed:%d\n", status);
 
 		return status;
@@ -1411,7 +1414,7 @@ static int sdw_handle_port_interrupt(struct sdw_slave *slave,
 		/* clear the interrupt but don't touch reserved fields */
 		ret = sdw_write_no_pm(slave, addr, clear);
 		if (ret < 0) {
-			dev_err(slave->bus->dev,
+			dev_err(&slave->dev,
 				"SDW_DPN_INT write failed:%d\n", ret);
 			return ret;
 		}
@@ -1419,7 +1422,7 @@ static int sdw_handle_port_interrupt(struct sdw_slave *slave,
 		/* Read DPN interrupt again */
 		status2 = sdw_read_no_pm(slave, addr);
 		if (status2 < 0) {
-			dev_err(slave->bus->dev,
+			dev_err(&slave->dev,
 				"SDW_DPN_INT read failed:%d\n", status2);
 			return status2;
 		}
@@ -1432,7 +1435,7 @@ static int sdw_handle_port_interrupt(struct sdw_slave *slave,
 	} while ((status & SDW_DPN_INTERRUPTS) && (count < SDW_READ_INTR_CLEAR_RETRY));
 
 	if (count == SDW_READ_INTR_CLEAR_RETRY)
-		dev_warn(slave->bus->dev, "Reached MAX_RETRY on port read");
+		dev_warn(&slave->dev, "Reached MAX_RETRY on port read");
 
 	return ret;
 }
@@ -1461,7 +1464,7 @@ static int sdw_handle_slave_alerts(struct sdw_slave *slave)
 	/* Read Intstat 1, Intstat 2 and Intstat 3 registers */
 	ret = sdw_read_no_pm(slave, SDW_SCP_INT1);
 	if (ret < 0) {
-		dev_err(slave->bus->dev,
+		dev_err(&slave->dev,
 			"SDW_SCP_INT1 read failed:%d\n", ret);
 		goto io_err;
 	}
@@ -1469,7 +1472,7 @@ static int sdw_handle_slave_alerts(struct sdw_slave *slave)
 
 	ret = sdw_nread_no_pm(slave, SDW_SCP_INTSTAT2, 2, buf2);
 	if (ret < 0) {
-		dev_err(slave->bus->dev,
+		dev_err(&slave->dev,
 			"SDW_SCP_INT2/3 read failed:%d\n", ret);
 		goto io_err;
 	}
@@ -1477,7 +1480,7 @@ static int sdw_handle_slave_alerts(struct sdw_slave *slave)
 	if (slave->prop.is_sdca) {
 		ret = sdw_read_no_pm(slave, SDW_DP0_INT);
 		if (ret < 0) {
-			dev_err(slave->bus->dev,
+			dev_err(&slave->dev,
 				"SDW_DP0_INT read failed:%d\n", ret);
 			goto io_err;
 		}
@@ -1574,7 +1577,7 @@ static int sdw_handle_slave_alerts(struct sdw_slave *slave)
 		/* Ack interrupt */
 		ret = sdw_write_no_pm(slave, SDW_SCP_INT1, clear);
 		if (ret < 0) {
-			dev_err(slave->bus->dev,
+			dev_err(&slave->dev,
 				"SDW_SCP_INT1 write failed:%d\n", ret);
 			goto io_err;
 		}
@@ -1588,7 +1591,7 @@ static int sdw_handle_slave_alerts(struct sdw_slave *slave)
 		 */
 		ret = sdw_read_no_pm(slave, SDW_SCP_INT1);
 		if (ret < 0) {
-			dev_err(slave->bus->dev,
+			dev_err(&slave->dev,
 				"SDW_SCP_INT1 read failed:%d\n", ret);
 			goto io_err;
 		}
@@ -1596,7 +1599,7 @@ static int sdw_handle_slave_alerts(struct sdw_slave *slave)
 
 		ret = sdw_nread_no_pm(slave, SDW_SCP_INTSTAT2, 2, _buf2);
 		if (ret < 0) {
-			dev_err(slave->bus->dev,
+			dev_err(&slave->dev,
 				"SDW_SCP_INT2/3 read failed:%d\n", ret);
 			goto io_err;
 		}
@@ -1604,7 +1607,7 @@ static int sdw_handle_slave_alerts(struct sdw_slave *slave)
 		if (slave->prop.is_sdca) {
 			ret = sdw_read_no_pm(slave, SDW_DP0_INT);
 			if (ret < 0) {
-				dev_err(slave->bus->dev,
+				dev_err(&slave->dev,
 					"SDW_DP0_INT read failed:%d\n", ret);
 				goto io_err;
 			}
@@ -1630,7 +1633,7 @@ static int sdw_handle_slave_alerts(struct sdw_slave *slave)
 	} while (stat != 0 && count < SDW_READ_INTR_CLEAR_RETRY);
 
 	if (count == SDW_READ_INTR_CLEAR_RETRY)
-		dev_warn(slave->bus->dev, "Reached MAX_RETRY on alert read\n");
+		dev_warn(&slave->dev, "Reached MAX_RETRY on alert read\n");
 
 io_err:
 	pm_runtime_mark_last_busy(&slave->dev);
@@ -1736,7 +1739,7 @@ int sdw_handle_slave_status(struct sdw_bus *bus,
 		case SDW_SLAVE_ALERT:
 			ret = sdw_handle_slave_alerts(slave);
 			if (ret)
-				dev_err(bus->dev,
+				dev_err(&slave->dev,
 					"Slave %d alert handling failed: %d\n",
 					i, ret);
 			break;
@@ -1755,21 +1758,21 @@ int sdw_handle_slave_status(struct sdw_bus *bus,
 
 			ret = sdw_initialize_slave(slave);
 			if (ret)
-				dev_err(bus->dev,
+				dev_err(&slave->dev,
 					"Slave %d initialization failed: %d\n",
 					i, ret);
 
 			break;
 
 		default:
-			dev_err(bus->dev, "Invalid slave %d status:%d\n",
+			dev_err(&slave->dev, "Invalid slave %d status:%d\n",
 				i, status[i]);
 			break;
 		}
 
 		ret = sdw_update_slave_status(slave, status[i]);
 		if (ret)
-			dev_err(slave->bus->dev,
+			dev_err(&slave->dev,
 				"Update Slave status failed:%d\n", ret);
 		if (attached_initializing)
 			complete(&slave->initialization_complete);
-- 
2.17.1


^ permalink raw reply	[flat|nested] 19+ messages in thread

* Re: [PATCH 1/7] soundwire: bus: use sdw_update_no_pm when initializing a device
  2020-12-02 20:46 ` [PATCH 1/7] soundwire: bus: use sdw_update_no_pm when initializing a device Bard Liao
@ 2020-12-05  7:45   ` Vinod Koul
  2020-12-05 14:59     ` Pierre-Louis Bossart
  0 siblings, 1 reply; 19+ messages in thread
From: Vinod Koul @ 2020-12-05  7:45 UTC (permalink / raw)
  To: Bard Liao
  Cc: alsa-devel, linux-kernel, tiwai, broonie, gregkh, jank,
	srinivas.kandagatla, rander.wang, ranjani.sridharan, hui.wang,
	pierre-louis.bossart, sanyog.r.kale, bard.liao

On 03-12-20, 04:46, Bard Liao wrote:
> From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
> 
> When a Slave device is resumed, it may resume the bus and restart the
> enumeration. During that process, we absolutely don't want to call
> regular read/write routines which will wait for the resume to
> complete, otherwise a deadlock occurs.
> 
> Fixes: 60ee9be25571 ('soundwire: bus: add PM/no-PM versions of read/write functions')

Change looks okay, but not sure why this is a fix for adding no pm
version?

> Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
> Reviewed-by: Rander Wang <rander.wang@linux.intel.com>
> Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
> ---
>  drivers/soundwire/bus.c | 16 ++++++++++++++--
>  1 file changed, 14 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c
> index d1e8c3a54976..60c42508c6c6 100644
> --- a/drivers/soundwire/bus.c
> +++ b/drivers/soundwire/bus.c
> @@ -489,6 +489,18 @@ sdw_read_no_pm(struct sdw_slave *slave, u32 addr)
>  		return buf;
>  }
>  
> +static int sdw_update_no_pm(struct sdw_slave *slave, u32 addr, u8 mask, u8 val)
> +{
> +	int tmp;
> +
> +	tmp = sdw_read_no_pm(slave, addr);
> +	if (tmp < 0)
> +		return tmp;
> +
> +	tmp = (tmp & ~mask) | val;
> +	return sdw_write_no_pm(slave, addr, tmp);
> +}
> +
>  /**
>   * sdw_nread() - Read "n" contiguous SDW Slave registers
>   * @slave: SDW Slave
> @@ -1256,7 +1268,7 @@ static int sdw_initialize_slave(struct sdw_slave *slave)
>  	val = slave->prop.scp_int1_mask;
>  
>  	/* Enable SCP interrupts */
> -	ret = sdw_update(slave, SDW_SCP_INTMASK1, val, val);
> +	ret = sdw_update_no_pm(slave, SDW_SCP_INTMASK1, val, val);
>  	if (ret < 0) {
>  		dev_err(slave->bus->dev,
>  			"SDW_SCP_INTMASK1 write failed:%d\n", ret);
> @@ -1271,7 +1283,7 @@ static int sdw_initialize_slave(struct sdw_slave *slave)
>  	val = prop->dp0_prop->imp_def_interrupts;
>  	val |= SDW_DP0_INT_PORT_READY | SDW_DP0_INT_BRA_FAILURE;
>  
> -	ret = sdw_update(slave, SDW_DP0_INTMASK, val, val);
> +	ret = sdw_update_no_pm(slave, SDW_DP0_INTMASK, val, val);
>  	if (ret < 0)
>  		dev_err(slave->bus->dev,
>  			"SDW_DP0_INTMASK read failed:%d\n", ret);
> -- 
> 2.17.1

-- 
~Vinod

^ permalink raw reply	[flat|nested] 19+ messages in thread

* Re: [PATCH 4/7] soundwire/regmap: use _no_pm functions in regmap_read/write
  2020-12-02 20:46 ` [PATCH 4/7] soundwire/regmap: use _no_pm functions in regmap_read/write Bard Liao
@ 2020-12-05  7:45   ` Vinod Koul
  2020-12-05 14:43     ` Pierre-Louis Bossart
  0 siblings, 1 reply; 19+ messages in thread
From: Vinod Koul @ 2020-12-05  7:45 UTC (permalink / raw)
  To: Bard Liao
  Cc: alsa-devel, linux-kernel, tiwai, broonie, gregkh, jank,
	srinivas.kandagatla, rander.wang, ranjani.sridharan, hui.wang,
	pierre-louis.bossart, sanyog.r.kale, bard.liao

On 03-12-20, 04:46, Bard Liao wrote:
> sdw_update_slave_status will be invoked when a codec is attached,
> and the codec driver will initialize the codec with regmap functions
> while the codec device is pm_runtime suspended.
> 
> regmap routines currently rely on regular SoundWire IO functions,
> which will call pm_runtime_get_sync()/put_autosuspend.
> 
> This causes a deadlock where the resume routine waits for an
> initialization complete signal that while the initialization complete
> can only be reached when the resume completes.
> 
> The only solution if we allow regmap functions to be used in resume
> operations as well as during codec initialization is to use _no_pm
> routines. The duty of making sure the bus is operational needs to be
> handled above the regmap level.
> 
> Fixes: 7c22ce6e21840 ('regmap: Add SoundWire bus support')
> Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
> Reviewed-by: Rander Wang <rander.wang@linux.intel.com>
> ---
>  drivers/base/regmap/regmap-sdw.c | 4 ++--
>  drivers/soundwire/bus.c          | 6 ++++--
>  include/linux/soundwire/sdw.h    | 2 ++
>  3 files changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/base/regmap/regmap-sdw.c b/drivers/base/regmap/regmap-sdw.c
> index c92d614b4943..4b8d2d010cab 100644
> --- a/drivers/base/regmap/regmap-sdw.c
> +++ b/drivers/base/regmap/regmap-sdw.c
> @@ -11,7 +11,7 @@ static int regmap_sdw_write(void *context, unsigned int reg, unsigned int val)
>  	struct device *dev = context;
>  	struct sdw_slave *slave = dev_to_sdw_dev(dev);
>  
> -	return sdw_write(slave, reg, val);
> +	return sdw_write_no_pm(slave, reg, val);
>  }
>  
>  static int regmap_sdw_read(void *context, unsigned int reg, unsigned int *val)
> @@ -20,7 +20,7 @@ static int regmap_sdw_read(void *context, unsigned int reg, unsigned int *val)
>  	struct sdw_slave *slave = dev_to_sdw_dev(dev);
>  	int read;
>  
> -	read = sdw_read(slave, reg);
> +	read = sdw_read_no_pm(slave, reg);
>  	if (read < 0)
>  		return read;
>  
> diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c
> index 86c339d77a39..c5ea59673dee 100644
> --- a/drivers/soundwire/bus.c
> +++ b/drivers/soundwire/bus.c
> @@ -405,10 +405,11 @@ sdw_nwrite_no_pm(struct sdw_slave *slave, u32 addr, size_t count, u8 *val)
>  	return sdw_transfer(slave->bus, &msg);
>  }
>  
> -static int sdw_write_no_pm(struct sdw_slave *slave, u32 addr, u8 value)
> +int sdw_write_no_pm(struct sdw_slave *slave, u32 addr, u8 value)
>  {
>  	return sdw_nwrite_no_pm(slave, addr, 1, &value);
>  }
> +EXPORT_SYMBOL(sdw_write_no_pm);

Why not export this is patch 1..?

>  
>  static int
>  sdw_bread_no_pm(struct sdw_bus *bus, u16 dev_num, u32 addr)
> @@ -476,7 +477,7 @@ int sdw_bwrite_no_pm_unlocked(struct sdw_bus *bus, u16 dev_num, u32 addr, u8 val
>  }
>  EXPORT_SYMBOL(sdw_bwrite_no_pm_unlocked);
>  
> -static int
> +int
>  sdw_read_no_pm(struct sdw_slave *slave, u32 addr)
>  {
>  	u8 buf;
> @@ -488,6 +489,7 @@ sdw_read_no_pm(struct sdw_slave *slave, u32 addr)
>  	else
>  		return buf;
>  }
> +EXPORT_SYMBOL(sdw_read_no_pm);
>  
>  static int sdw_update_no_pm(struct sdw_slave *slave, u32 addr, u8 mask, u8 val)
>  {
> diff --git a/include/linux/soundwire/sdw.h b/include/linux/soundwire/sdw.h
> index f0b01b728640..d08039d65825 100644
> --- a/include/linux/soundwire/sdw.h
> +++ b/include/linux/soundwire/sdw.h
> @@ -1005,6 +1005,8 @@ int sdw_bus_exit_clk_stop(struct sdw_bus *bus);
>  
>  int sdw_read(struct sdw_slave *slave, u32 addr);
>  int sdw_write(struct sdw_slave *slave, u32 addr, u8 value);
> +int sdw_write_no_pm(struct sdw_slave *slave, u32 addr, u8 value);
> +int sdw_read_no_pm(struct sdw_slave *slave, u32 addr);
>  int sdw_nread(struct sdw_slave *slave, u32 addr, size_t count, u8 *val);
>  int sdw_nwrite(struct sdw_slave *slave, u32 addr, size_t count, u8 *val);
>  
> -- 
> 2.17.1

-- 
~Vinod

^ permalink raw reply	[flat|nested] 19+ messages in thread

* Re: [PATCH 5/7] regmap: sdw: use no_pm routines for SoundWire 1.2 MBQ
  2020-12-02 20:46 ` [PATCH 5/7] regmap: sdw: use no_pm routines for SoundWire 1.2 MBQ Bard Liao
@ 2020-12-05  7:46   ` Vinod Koul
  2020-12-05 14:52     ` Pierre-Louis Bossart
  0 siblings, 1 reply; 19+ messages in thread
From: Vinod Koul @ 2020-12-05  7:46 UTC (permalink / raw)
  To: Bard Liao
  Cc: alsa-devel, linux-kernel, tiwai, broonie, gregkh, jank,
	srinivas.kandagatla, rander.wang, ranjani.sridharan, hui.wang,
	pierre-louis.bossart, sanyog.r.kale, bard.liao

On 03-12-20, 04:46, Bard Liao wrote:

>  MODULE_DESCRIPTION("Regmap SoundWire MBQ Module");
> -MODULE_LICENSE("GPL v2");
> +MODULE_LICENSE("GPL");

Why do you want to change this ?

> -- 
> 2.17.1

-- 
~Vinod

^ permalink raw reply	[flat|nested] 19+ messages in thread

* Re: [PATCH 4/7] soundwire/regmap: use _no_pm functions in regmap_read/write
  2020-12-05  7:45   ` Vinod Koul
@ 2020-12-05 14:43     ` Pierre-Louis Bossart
  0 siblings, 0 replies; 19+ messages in thread
From: Pierre-Louis Bossart @ 2020-12-05 14:43 UTC (permalink / raw)
  To: Vinod Koul, Bard Liao
  Cc: alsa-devel, tiwai, gregkh, linux-kernel, ranjani.sridharan,
	hui.wang, broonie, srinivas.kandagatla, jank, sanyog.r.kale,
	rander.wang, bard.liao


>> -static int sdw_write_no_pm(struct sdw_slave *slave, u32 addr, u8 value)
>> +int sdw_write_no_pm(struct sdw_slave *slave, u32 addr, u8 value)
>>   {
>>   	return sdw_nwrite_no_pm(slave, addr, 1, &value);
>>   }
>> +EXPORT_SYMBOL(sdw_write_no_pm);
> 
> Why not export this is patch 1..?

yes, good point. I guess Bard and I were debugging in parallel and 
missed this. thanks for pointing it out.

^ permalink raw reply	[flat|nested] 19+ messages in thread

* Re: [PATCH 5/7] regmap: sdw: use no_pm routines for SoundWire 1.2 MBQ
  2020-12-05  7:46   ` Vinod Koul
@ 2020-12-05 14:52     ` Pierre-Louis Bossart
  2020-12-05 16:31       ` Greg KH
  0 siblings, 1 reply; 19+ messages in thread
From: Pierre-Louis Bossart @ 2020-12-05 14:52 UTC (permalink / raw)
  To: Vinod Koul, Bard Liao
  Cc: alsa-devel, tiwai, gregkh, linux-kernel, ranjani.sridharan,
	hui.wang, broonie, srinivas.kandagatla, jank, sanyog.r.kale,
	rander.wang, bard.liao


>>   MODULE_DESCRIPTION("Regmap SoundWire MBQ Module");
>> -MODULE_LICENSE("GPL v2");
>> +MODULE_LICENSE("GPL");
> 
> Why do you want to change this ?

We only use MODULE_LICENSE("GPL") for new contributions since 'GPL v2' 
does not bring any information on the license, is equivalent to 'GPL' 
and only exists for 'historical reasons', see

https://www.kernel.org/doc/html/latest/process/license-rules.html


“GPL”	Module is licensed under GPL version 2. This does not express any 
distinction between GPL-2.0-only or GPL-2.0-or-later. The exact license 
information can only be determined via the license information in the 
corresponding source files.

“GPL v2”	Same as “GPL”. It exists for historic reasons.

We should have used 'GPL' in the initial regmap MBQ patch but didn't for 
some reason, this change just realigns with what we intended.

That said, this is unrelated to this no_pm patch so could be in a 
separate one if you preferred it that way.

^ permalink raw reply	[flat|nested] 19+ messages in thread

* Re: [PATCH 1/7] soundwire: bus: use sdw_update_no_pm when initializing a device
  2020-12-05  7:45   ` Vinod Koul
@ 2020-12-05 14:59     ` Pierre-Louis Bossart
  2020-12-07  4:43       ` Vinod Koul
  0 siblings, 1 reply; 19+ messages in thread
From: Pierre-Louis Bossart @ 2020-12-05 14:59 UTC (permalink / raw)
  To: Vinod Koul, Bard Liao
  Cc: alsa-devel, tiwai, gregkh, linux-kernel, ranjani.sridharan,
	hui.wang, broonie, srinivas.kandagatla, jank, sanyog.r.kale,
	rander.wang, bard.liao

Thanks for the review Vinod.

On 12/5/20 1:45 AM, Vinod Koul wrote:
> On 03-12-20, 04:46, Bard Liao wrote:
>> From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
>>
>> When a Slave device is resumed, it may resume the bus and restart the
>> enumeration. During that process, we absolutely don't want to call
>> regular read/write routines which will wait for the resume to
>> complete, otherwise a deadlock occurs.
>>
>> Fixes: 60ee9be25571 ('soundwire: bus: add PM/no-PM versions of read/write functions')
> 
> Change looks okay, but not sure why this is a fix for adding no pm
> version?

when we added the no_pm version, we missed the two cases below where 
sdw_update() was used and that creates a deadlock. To me that's a 
conceptual bug, we didn't fully use the no_pm versions, hence the Fixes tag.

It's ok to remove the tag if you don't think it's useful/relevant, what 
matters is that we agree on the content.

>> Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
>> Reviewed-by: Rander Wang <rander.wang@linux.intel.com>
>> Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
>> ---
>>   drivers/soundwire/bus.c | 16 ++++++++++++++--
>>   1 file changed, 14 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c
>> index d1e8c3a54976..60c42508c6c6 100644
>> --- a/drivers/soundwire/bus.c
>> +++ b/drivers/soundwire/bus.c
>> @@ -489,6 +489,18 @@ sdw_read_no_pm(struct sdw_slave *slave, u32 addr)
>>   		return buf;
>>   }
>>   
>> +static int sdw_update_no_pm(struct sdw_slave *slave, u32 addr, u8 mask, u8 val)
>> +{
>> +	int tmp;
>> +
>> +	tmp = sdw_read_no_pm(slave, addr);
>> +	if (tmp < 0)
>> +		return tmp;
>> +
>> +	tmp = (tmp & ~mask) | val;
>> +	return sdw_write_no_pm(slave, addr, tmp);
>> +}
>> +
>>   /**
>>    * sdw_nread() - Read "n" contiguous SDW Slave registers
>>    * @slave: SDW Slave
>> @@ -1256,7 +1268,7 @@ static int sdw_initialize_slave(struct sdw_slave *slave)
>>   	val = slave->prop.scp_int1_mask;
>>   
>>   	/* Enable SCP interrupts */
>> -	ret = sdw_update(slave, SDW_SCP_INTMASK1, val, val);
>> +	ret = sdw_update_no_pm(slave, SDW_SCP_INTMASK1, val, val);
>>   	if (ret < 0) {
>>   		dev_err(slave->bus->dev,
>>   			"SDW_SCP_INTMASK1 write failed:%d\n", ret);
>> @@ -1271,7 +1283,7 @@ static int sdw_initialize_slave(struct sdw_slave *slave)
>>   	val = prop->dp0_prop->imp_def_interrupts;
>>   	val |= SDW_DP0_INT_PORT_READY | SDW_DP0_INT_BRA_FAILURE;
>>   
>> -	ret = sdw_update(slave, SDW_DP0_INTMASK, val, val);
>> +	ret = sdw_update_no_pm(slave, SDW_DP0_INTMASK, val, val);
>>   	if (ret < 0)
>>   		dev_err(slave->bus->dev,
>>   			"SDW_DP0_INTMASK read failed:%d\n", ret);
>> -- 
>> 2.17.1
> 

^ permalink raw reply	[flat|nested] 19+ messages in thread

* Re: [PATCH 5/7] regmap: sdw: use no_pm routines for SoundWire 1.2 MBQ
  2020-12-05 14:52     ` Pierre-Louis Bossart
@ 2020-12-05 16:31       ` Greg KH
  2020-12-07  4:47         ` Vinod Koul
  0 siblings, 1 reply; 19+ messages in thread
From: Greg KH @ 2020-12-05 16:31 UTC (permalink / raw)
  To: Pierre-Louis Bossart
  Cc: Vinod Koul, Bard Liao, alsa-devel, tiwai, linux-kernel,
	ranjani.sridharan, hui.wang, broonie, srinivas.kandagatla, jank,
	sanyog.r.kale, rander.wang, bard.liao

On Sat, Dec 05, 2020 at 08:52:50AM -0600, Pierre-Louis Bossart wrote:
> 
> > >   MODULE_DESCRIPTION("Regmap SoundWire MBQ Module");
> > > -MODULE_LICENSE("GPL v2");
> > > +MODULE_LICENSE("GPL");
> > 
> > Why do you want to change this ?
> 
> We only use MODULE_LICENSE("GPL") for new contributions since 'GPL v2' does
> not bring any information on the license, is equivalent to 'GPL' and only
> exists for 'historical reasons', see
> 
> https://www.kernel.org/doc/html/latest/process/license-rules.html
> 
> 
> “GPL”	Module is licensed under GPL version 2. This does not express any
> distinction between GPL-2.0-only or GPL-2.0-or-later. The exact license
> information can only be determined via the license information in the
> corresponding source files.
> 
> “GPL v2”	Same as “GPL”. It exists for historic reasons.
> 
> We should have used 'GPL' in the initial regmap MBQ patch but didn't for
> some reason, this change just realigns with what we intended.
> 
> That said, this is unrelated to this no_pm patch so could be in a separate
> one if you preferred it that way.

It should be separate as it does not have anything to do with the real
reason this patch was submitted.

thanks,

greg k-h

^ permalink raw reply	[flat|nested] 19+ messages in thread

* Re: [PATCH 1/7] soundwire: bus: use sdw_update_no_pm when initializing a device
  2020-12-05 14:59     ` Pierre-Louis Bossart
@ 2020-12-07  4:43       ` Vinod Koul
  2020-12-07 15:31         ` Pierre-Louis Bossart
  0 siblings, 1 reply; 19+ messages in thread
From: Vinod Koul @ 2020-12-07  4:43 UTC (permalink / raw)
  To: Pierre-Louis Bossart
  Cc: Bard Liao, alsa-devel, tiwai, gregkh, linux-kernel,
	ranjani.sridharan, hui.wang, broonie, srinivas.kandagatla, jank,
	sanyog.r.kale, rander.wang, bard.liao

On 05-12-20, 08:59, Pierre-Louis Bossart wrote:
> Thanks for the review Vinod.
> 
> On 12/5/20 1:45 AM, Vinod Koul wrote:
> > On 03-12-20, 04:46, Bard Liao wrote:
> > > From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
> > > 
> > > When a Slave device is resumed, it may resume the bus and restart the
> > > enumeration. During that process, we absolutely don't want to call
> > > regular read/write routines which will wait for the resume to
> > > complete, otherwise a deadlock occurs.
> > > 
> > > Fixes: 60ee9be25571 ('soundwire: bus: add PM/no-PM versions of read/write functions')
> > 
> > Change looks okay, but not sure why this is a fix for adding no pm
> > version?
> 
> when we added the no_pm version, we missed the two cases below where
> sdw_update() was used and that creates a deadlock. To me that's a conceptual
> bug, we didn't fully use the no_pm versions, hence the Fixes tag.

Documentation says:
"A Fixes: tag indicates that the patch fixes an issue in a previous commit. It
is used to make it easy to determine where a bug originated, which can help
review a bug fix. This tag also assists the stable kernel team in determining
which stable kernel versions should receive your fix. This is the preferred
method for indicating a bug fixed by the patch. See :ref:`describe_changes`
for more details."

I do not this this helps here as this does not help distros etc
I would say this is incremental development which improved a case not
done properly earlier, unless you would like this to be backported.. In
that case it helps folks...

> It's ok to remove the tag if you don't think it's useful/relevant, what
> matters is that we agree on the content.

-- 
~Vinod

^ permalink raw reply	[flat|nested] 19+ messages in thread

* Re: [PATCH 5/7] regmap: sdw: use no_pm routines for SoundWire 1.2 MBQ
  2020-12-05 16:31       ` Greg KH
@ 2020-12-07  4:47         ` Vinod Koul
  0 siblings, 0 replies; 19+ messages in thread
From: Vinod Koul @ 2020-12-07  4:47 UTC (permalink / raw)
  To: Greg KH
  Cc: Pierre-Louis Bossart, Bard Liao, alsa-devel, tiwai, linux-kernel,
	ranjani.sridharan, hui.wang, broonie, srinivas.kandagatla, jank,
	sanyog.r.kale, rander.wang, bard.liao

On 05-12-20, 17:31, Greg KH wrote:
> On Sat, Dec 05, 2020 at 08:52:50AM -0600, Pierre-Louis Bossart wrote:
> > 
> > > >   MODULE_DESCRIPTION("Regmap SoundWire MBQ Module");
> > > > -MODULE_LICENSE("GPL v2");
> > > > +MODULE_LICENSE("GPL");
> > > 
> > > Why do you want to change this ?
> > 
> > We only use MODULE_LICENSE("GPL") for new contributions since 'GPL v2' does
> > not bring any information on the license, is equivalent to 'GPL' and only
> > exists for 'historical reasons', see
> > 
> > https://www.kernel.org/doc/html/latest/process/license-rules.html
> > 
> > 
> > “GPL”	Module is licensed under GPL version 2. This does not express any
> > distinction between GPL-2.0-only or GPL-2.0-or-later. The exact license
> > information can only be determined via the license information in the
> > corresponding source files.
> > 
> > “GPL v2”	Same as “GPL”. It exists for historic reasons.
> > 
> > We should have used 'GPL' in the initial regmap MBQ patch but didn't for
> > some reason, this change just realigns with what we intended.
> > 
> > That said, this is unrelated to this no_pm patch so could be in a separate
> > one if you preferred it that way.
> 
> It should be separate as it does not have anything to do with the real
> reason this patch was submitted.

Precisely, this should be a separate patch explaining the motivation
behind this change.

-- 
~Vinod

^ permalink raw reply	[flat|nested] 19+ messages in thread

* Re: [PATCH 1/7] soundwire: bus: use sdw_update_no_pm when initializing a device
  2020-12-07  4:43       ` Vinod Koul
@ 2020-12-07 15:31         ` Pierre-Louis Bossart
  2020-12-08  4:56           ` Vinod Koul
  0 siblings, 1 reply; 19+ messages in thread
From: Pierre-Louis Bossart @ 2020-12-07 15:31 UTC (permalink / raw)
  To: Vinod Koul
  Cc: Bard Liao, alsa-devel, tiwai, gregkh, linux-kernel,
	ranjani.sridharan, hui.wang, broonie, srinivas.kandagatla, jank,
	sanyog.r.kale, rander.wang, bard.liao



On 12/6/20 10:43 PM, Vinod Koul wrote:
> On 05-12-20, 08:59, Pierre-Louis Bossart wrote:
>> Thanks for the review Vinod.
>>
>> On 12/5/20 1:45 AM, Vinod Koul wrote:
>>> On 03-12-20, 04:46, Bard Liao wrote:
>>>> From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
>>>>
>>>> When a Slave device is resumed, it may resume the bus and restart the
>>>> enumeration. During that process, we absolutely don't want to call
>>>> regular read/write routines which will wait for the resume to
>>>> complete, otherwise a deadlock occurs.
>>>>
>>>> Fixes: 60ee9be25571 ('soundwire: bus: add PM/no-PM versions of read/write functions')
>>>
>>> Change looks okay, but not sure why this is a fix for adding no pm
>>> version?
>>
>> when we added the no_pm version, we missed the two cases below where
>> sdw_update() was used and that creates a deadlock. To me that's a conceptual
>> bug, we didn't fully use the no_pm versions, hence the Fixes tag.
> 
> Documentation says:
> "A Fixes: tag indicates that the patch fixes an issue in a previous commit. It
> is used to make it easy to determine where a bug originated, which can help
> review a bug fix. This tag also assists the stable kernel team in determining
> which stable kernel versions should receive your fix. This is the preferred
> method for indicating a bug fixed by the patch. See :ref:`describe_changes`
> for more details."
> 
> I do not this this helps here as this does not help distros etc
> I would say this is incremental development which improved a case not
> done properly earlier, unless you would like this to be backported.. In
> that case it helps folks...

IMHO the changes in the series are absolutely required to have a 
reliable suspend-resume operation and will need to be back-ported. When 
I said 'conceptual bug', I didn't mean a hypothetical case, I really 
meant that a proven race condition and timeouts will occur. That's not 
good... We will provide the list of this patches to distros that are 
known to support SoundWire as a 'must apply'.

If you look at the series, we provided Fixes tags for all patches except 
'cosmetic' ones which don't fundamentally change the behavior (Patch 3, 
patch 7) or when the code has not reached Linus' tree (patch 5).

That said, 5.10 was the first release where SoundWire started to be 
functional so there's no need to apply these patches to earlier versions 
of the stable tree.

Does this help?

^ permalink raw reply	[flat|nested] 19+ messages in thread

* Re: [PATCH 1/7] soundwire: bus: use sdw_update_no_pm when initializing a device
  2020-12-07 15:31         ` Pierre-Louis Bossart
@ 2020-12-08  4:56           ` Vinod Koul
  0 siblings, 0 replies; 19+ messages in thread
From: Vinod Koul @ 2020-12-08  4:56 UTC (permalink / raw)
  To: Pierre-Louis Bossart
  Cc: Bard Liao, alsa-devel, tiwai, gregkh, linux-kernel,
	ranjani.sridharan, hui.wang, broonie, srinivas.kandagatla, jank,
	sanyog.r.kale, rander.wang, bard.liao

On 07-12-20, 09:31, Pierre-Louis Bossart wrote:
> On 12/6/20 10:43 PM, Vinod Koul wrote:
> > On 05-12-20, 08:59, Pierre-Louis Bossart wrote:
> > > Thanks for the review Vinod.
> > > 
> > > On 12/5/20 1:45 AM, Vinod Koul wrote:
> > > > On 03-12-20, 04:46, Bard Liao wrote:
> > > > > From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
> > > > > 
> > > > > When a Slave device is resumed, it may resume the bus and restart the
> > > > > enumeration. During that process, we absolutely don't want to call
> > > > > regular read/write routines which will wait for the resume to
> > > > > complete, otherwise a deadlock occurs.
> > > > > 
> > > > > Fixes: 60ee9be25571 ('soundwire: bus: add PM/no-PM versions of read/write functions')
> > > > 
> > > > Change looks okay, but not sure why this is a fix for adding no pm
> > > > version?
> > > 
> > > when we added the no_pm version, we missed the two cases below where
> > > sdw_update() was used and that creates a deadlock. To me that's a conceptual
> > > bug, we didn't fully use the no_pm versions, hence the Fixes tag.
> > 
> > Documentation says:
> > "A Fixes: tag indicates that the patch fixes an issue in a previous commit. It
> > is used to make it easy to determine where a bug originated, which can help
> > review a bug fix. This tag also assists the stable kernel team in determining
> > which stable kernel versions should receive your fix. This is the preferred
> > method for indicating a bug fixed by the patch. See :ref:`describe_changes`
> > for more details."
> > 
> > I do not this this helps here as this does not help distros etc
> > I would say this is incremental development which improved a case not
> > done properly earlier, unless you would like this to be backported.. In
> > that case it helps folks...
> 
> IMHO the changes in the series are absolutely required to have a reliable
> suspend-resume operation and will need to be back-ported. When I said
> 'conceptual bug', I didn't mean a hypothetical case, I really meant that a
> proven race condition and timeouts will occur. That's not good... We will
> provide the list of this patches to distros that are known to support
> SoundWire as a 'must apply'.
> 
> If you look at the series, we provided Fixes tags for all patches except
> 'cosmetic' ones which don't fundamentally change the behavior (Patch 3,
> patch 7) or when the code has not reached Linus' tree (patch 5).
> 
> That said, 5.10 was the first release where SoundWire started to be
> functional so there's no need to apply these patches to earlier versions of
> the stable tree.
> 
> Does this help?

Yes, that helps, thanks

-- 
~Vinod

^ permalink raw reply	[flat|nested] 19+ messages in thread

end of thread, other threads:[~2020-12-08  4:56 UTC | newest]

Thread overview: 19+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-12-02 20:46 [PATCH 0/7] soundwire/regmap: use _no_pm routines Bard Liao
2020-12-02 20:46 ` [PATCH 1/7] soundwire: bus: use sdw_update_no_pm when initializing a device Bard Liao
2020-12-05  7:45   ` Vinod Koul
2020-12-05 14:59     ` Pierre-Louis Bossart
2020-12-07  4:43       ` Vinod Koul
2020-12-07 15:31         ` Pierre-Louis Bossart
2020-12-08  4:56           ` Vinod Koul
2020-12-02 20:46 ` [PATCH 2/7] soundwire: bus: use sdw_write_no_pm when setting the bus scale registers Bard Liao
2020-12-02 20:46 ` [PATCH 3/7] soundwire: bus: use no_pm IO routines for all interrupt handling Bard Liao
2020-12-02 20:46 ` [PATCH 4/7] soundwire/regmap: use _no_pm functions in regmap_read/write Bard Liao
2020-12-05  7:45   ` Vinod Koul
2020-12-05 14:43     ` Pierre-Louis Bossart
2020-12-02 20:46 ` [PATCH 5/7] regmap: sdw: use no_pm routines for SoundWire 1.2 MBQ Bard Liao
2020-12-05  7:46   ` Vinod Koul
2020-12-05 14:52     ` Pierre-Louis Bossart
2020-12-05 16:31       ` Greg KH
2020-12-07  4:47         ` Vinod Koul
2020-12-02 20:46 ` [PATCH 6/7] soundwire: bus: fix confusion on device used by pm_runtime Bard Liao
2020-12-02 20:46 ` [PATCH 7/7] soundwire: bus: clarify dev_err/dbg device references Bard Liao

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