PM: core: Add pm_wakeup_pending check in device suspend_noirq

RFC In review cy_huang 2 participants 3 messages Sep 16, 2022 – Sep 22, 2022

Subsystems (4)

Driver core Suspend to RAM Hibernation Power management core

lore

Share & tools

lore

cy_huang

author

2022-09-16 02:15 UTC #0 lore raw

RFC 1/1 PM: core: Add pm_wakeup_pending check in device suspend_noirq

From: ChiYuan Huang <[email protected]>

In 'dpm_suspend_noirq', it will do the sychronized_irq to guarantee all irqs are all done, and then do any wakeup flag set.

For some peripherial deivces like as I2C/SPI, to speed up the irq handling, it may use 'pm_stay_awake' and really handle in another thread context like as workqueue.

But in mem suspend flow, after 'dpm_suspend_noirq" stage, the next 'pm_wakeup_pending' check will be at 'syscore_suspend'.

The checkpoint seems too late and cause I2C/SPI fail during 'noirq' to 'syscore_suspend'. But some adapter was already be marked as 'suspended' at 'noirq' callback, any I2C/SPI xfer will return the error flag '-ESHUTDOWN'.

After the code trace, it seems all device callback will do 'pm_wakeup_pending' check, except 'noirq'.

This patch is to add 'pm_wakeup_pending' check in 'noirq' sage to prevent this kind of usage.

Signed-off-by ChiYuan Huang <[email protected]>

---
Hi,

Is there any rule to define when I2C/SPI host controller need to mark adapter as 'suspended'?

I trace 'drivers/i2c/buses'.It seems there's no common rule, Some are 'suspend', others may did it at 'suspend_noirq'.

---
 drivers/base/power/main.c | 5 +++++
 1 file changed, 5 insertions(+)

drivers/base/power/main.c +5 -0

index c501392..7cd7dc5 100644
@@ -1210,6 +1210,11 @@ static int __device_suspend_noirq(struct device *dev, pm_message_t state, bool a
 	if (async_error)
 		goto Complete;
 
+	if (pm_wakeup_pending()) {
+		async_error = -EBUSY;
+		goto Complete;
+	}
+
 	if (dev->power.syscore || dev->power.direct_complete)
 		goto Complete;

Signature · 1 line

2.7.4

Rafael J. Wysocki

maintainer

2022-09-21 18:13 UTC #1 lore raw

Quoted 10 lines · cy_huang

From: ChiYuan Huang <[email protected]>
In 'dpm_suspend_noirq', it will do the sychronized_irq to guarantee all irqs are all done, and then do any wakeup flag set.
For some peripherial deivces like as I2C/SPI, to speed up the irq handling, it may use 'pm_stay_awake' and really handle in another thread context like as workqueue.

Quoted 5 lines

But in mem suspend flow, after 'dpm_suspend_noirq" stage, the next 'pm_wakeup_pending' check will be at 'syscore_suspend'.
The checkpoint seems too late and cause I2C/SPI fail during 'noirq' to 'syscore_suspend'

What exactly do you mean by "fail" here?

Quoted 42 lines

. But some adapter was already be marked as 'suspended'
at 'noirq' callback, any I2C/SPI xfer will return the error flag '-ESHUTDOWN'.
After the code trace, it seems all device callback will do 'pm_wakeup_pending' check, except 'noirq'.
This patch is to add 'pm_wakeup_pending' check in 'noirq' sage to prevent this kind of usage.
Signed-off-by ChiYuan Huang <[email protected]>
---
Hi,
Is there any rule to define when I2C/SPI host controller need to mark adapter as 'suspended'?
I trace 'drivers/i2c/buses'.It seems there's no common rule, Some are 'suspend', others may did it at 'suspend_noirq'.
---
 drivers/base/power/main.c | 5 +++++
 1 file changed, 5 insertions(+)
drivers/base/power/main.c +5 -1
index c501392..7cd7dc5 100644
@@ -1210,6 +1210,11 @@ static int __device_suspend_noirq(struct device *dev, pm_message_t state, bool a
        if (async_error)
                goto Complete;
 
+       if (pm_wakeup_pending()) {
+               async_error = -EBUSY;
+               goto Complete;
+       }
+
        if (dev->power.syscore || dev->power.direct_complete)
                goto Complete;
 
--
2.7.4

ChiYuan Huang

author

2022-09-22 00:34 UTC #2 lore raw

Rafael J. Wysocki <[email protected]> 於 2022年9月22日週四凌晨2:13寫道：

Quoted 12 lines · cy_huang

Quoted 10 lines
From: ChiYuan Huang <[email protected]>
In 'dpm_suspend_noirq', it will do the sychronized_irq to guarantee all irqs are all done, and then do any wakeup flag set.
For some peripherial deivces like as I2C/SPI, to speed up the irq handling, it may use 'pm_stay_awake' and really handle in another thread context like as workqueue.

Quoted 7 lines

Quoted 5 lines
But in mem suspend flow, after 'dpm_suspend_noirq" stage, the next 'pm_wakeup_pending' check will be at 'syscore_suspend'.
The checkpoint seems too late and cause I2C/SPI fail during 'noirq' to 'syscore_suspend'
What exactly do you mean by "fail" here?

For the below case
Once the adapter is marked as 'Suspend', any i2c_xfer or spi_xfer will directly return 'ESHUTDOWN".
There's no real I/O transferred, only the direct returned error code.

Quoted 43 lines

Quoted 43 lines
. But some adapter was already be marked as 'suspended'
at 'noirq' callback, any I2C/SPI xfer will return the error flag '-ESHUTDOWN'.
After the code trace, it seems all device callback will do 'pm_wakeup_pending' check, except 'noirq'.
This patch is to add 'pm_wakeup_pending' check in 'noirq' sage to prevent this kind of usage.
Signed-off-by ChiYuan Huang <[email protected]>
---
Hi,
Is there any rule to define when I2C/SPI host controller need to mark adapter as 'suspended'?
I trace 'drivers/i2c/buses'.It seems there's no common rule, Some are 'suspend', others may did it at 'suspend_noirq'.
---
 drivers/base/power/main.c | 5 +++++
 1 file changed, 5 insertions(+)
drivers/base/power/main.c +5 -1
index c501392..7cd7dc5 100644
@@ -1210,6 +1210,11 @@ static int __device_suspend_noirq(struct device *dev, pm_message_t state, bool a
        if (async_error)
                goto Complete;
 
+       if (pm_wakeup_pending()) {
+               async_error = -EBUSY;
+               goto Complete;
+       }
+
        if (dev->power.syscore || dev->power.direct_complete)
                goto Complete;
 
--
2.7.4