[PATCH] i2c: rk3x: keep i2c irq ON in suspend

[PATCH] i2c: rk3x: keep i2c irq ON in suspend

[David Wu]

During suspend there may still be some i2c access happening.
And if we don't keep i2c irq ON, there may be i2c access timeout if
i2c is in irq mode of operation.

Signed-off-by: David Wu <david.wu@rock-chips.com>
---
 drivers/i2c/busses/i2c-rk3x.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x.c
index df22066..67af32a 100644
--- a/drivers/i2c/busses/i2c-rk3x.c
+++ b/drivers/i2c/busses/i2c-rk3x.c
@@ -1261,7 +1261,7 @@ static int rk3x_i2c_probe(struct platform_device *pdev)
 	}
 
 	ret = devm_request_irq(&pdev->dev, irq, rk3x_i2c_irq,
-			       0, dev_name(&pdev->dev), i2c);
+			       IRQF_NO_SUSPEND, dev_name(&pdev->dev), i2c);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "cannot request IRQ\n");
 		return ret;
-- 
1.9.1

Re: [PATCH] i2c: rk3x: keep i2c irq ON in suspend

[Heiko Stuebner]

Hi David,

Am Montag, 5. Dezember 2016, 16:02:59 CET schrieb David Wu:
> During suspend there may still be some i2c access happening.
> And if we don't keep i2c irq ON, there may be i2c access timeout if
> i2c is in irq mode of operation.

can you describe the issue you're trying to fix a bit more please?

I.e. I'd think the i2c-core does suspend i2c-client devices first, so that
these should be able to finish up their ongoing transfers and not start any
new ones instead?

Your irq can still happen slightly after the system started going to actually
sleep, so to me it looks like you just widened the window where irqs can be
handled. Especially as your irq could also just simply stem from the start
state, so you cannot even be sure if your transaction actually is finished.

So to me it looks like the i2c-connected device driver should be fixed instead?

In the past I solved this for example in the zforce_ts driver [0] to
prevent i2c transfers from happening during suspend.


Heiko

[0] https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/input/touchscreen/zforce_ts.c


> 
> Signed-off-by: David Wu <david.wu@rock-chips.com>
> ---
>  drivers/i2c/busses/i2c-rk3x.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x.c
> index df22066..67af32a 100644
> --- a/drivers/i2c/busses/i2c-rk3x.c
> +++ b/drivers/i2c/busses/i2c-rk3x.c
> @@ -1261,7 +1261,7 @@ static int rk3x_i2c_probe(struct platform_device
> *pdev) }
> 
>  	ret = devm_request_irq(&pdev->dev, irq, rk3x_i2c_irq,
> -			       0, dev_name(&pdev->dev), i2c);
> +			       IRQF_NO_SUSPEND, dev_name(&pdev->dev), i2c);
>  	if (ret < 0) {
>  		dev_err(&pdev->dev, "cannot request IRQ\n");
>  		return ret;

Re: [PATCH] i2c: rk3x: keep i2c irq ON in suspend

[David.Wu]

Hi Heiko,

在 2016/12/5 18:54, Heiko Stuebner 写道:
> Hi David,
>
> Am Montag, 5. Dezember 2016, 16:02:59 CET schrieb David Wu:
>> During suspend there may still be some i2c access happening.
>> And if we don't keep i2c irq ON, there may be i2c access timeout if
>> i2c is in irq mode of operation.
>
> can you describe the issue you're trying to fix a bit more please?

Sometimes we could see the i2c timeout errors during suspend/resume, 
which makes the duration of suspend/resume too longer.

[  484.171541] CPU4: Booted secondary processor [410fd082]
[  485.172777] rk3x-i2c ff3c0000.i2c: timeout, ipd: 0x10, state: 1
[  486.172760] rk3x-i2c ff3c0000.i2c: timeout, ipd: 0x10, state: 1
[  487.172759] rk3x-i2c ff3c0000.i2c: timeout, ipd: 0x10, state: 1
[  487.172840] cpu cpu4: _set_opp_voltage: failed to set voltage (800000 
800000 800000 mV): -110
[  487.172874] cpu cpu4: failed to set volt 800000

>
> I.e. I'd think the i2c-core does suspend i2c-client devices first, so that
> these should be able to finish up their ongoing transfers and not start any
> new ones instead?
>
> Your irq can still happen slightly after the system started going to actually
> sleep, so to me it looks like you just widened the window where irqs can be
> handled. Especially as your irq could also just simply stem from the start
> state, so you cannot even be sure if your transaction actually is finished.

Okay, you are right. I want to give it a double insurance at first, but 
it may hide the unhappend issue.

>
> So to me it looks like the i2c-connected device driver should be fixed instead?

I tell them to fix it in rk808 driver.

>
> In the past I solved this for example in the zforce_ts driver [0] to
> prevent i2c transfers from happening during suspend.
>
>
> Heiko
>
> [0] https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/input/touchscreen/zforce_ts.c
>
>
>>
>> Signed-off-by: David Wu <david.wu@rock-chips.com>
>> ---
>>  drivers/i2c/busses/i2c-rk3x.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x.c
>> index df22066..67af32a 100644
>> --- a/drivers/i2c/busses/i2c-rk3x.c
>> +++ b/drivers/i2c/busses/i2c-rk3x.c
>> @@ -1261,7 +1261,7 @@ static int rk3x_i2c_probe(struct platform_device
>> *pdev) }
>>
>>  	ret = devm_request_irq(&pdev->dev, irq, rk3x_i2c_irq,
>> -			       0, dev_name(&pdev->dev), i2c);
>> +			       IRQF_NO_SUSPEND, dev_name(&pdev->dev), i2c);
>>  	if (ret < 0) {
>>  		dev_err(&pdev->dev, "cannot request IRQ\n");
>>  		return ret;
>
>
>
>
>

Re: [PATCH] i2c: rk3x: keep i2c irq ON in suspend

[Doug Anderson]

Hi,

On Tue, Dec 6, 2016 at 12:12 AM, David.Wu <david.wu@rock-chips.com> wrote:
> Hi Heiko,
>
> 在 2016/12/5 18:54, Heiko Stuebner 写道:
>>
>> Hi David,
>>
>> Am Montag, 5. Dezember 2016, 16:02:59 CET schrieb David Wu:
>>>
>>> During suspend there may still be some i2c access happening.
>>> And if we don't keep i2c irq ON, there may be i2c access timeout if
>>> i2c is in irq mode of operation.
>>
>>
>> can you describe the issue you're trying to fix a bit more please?
>
>
> Sometimes we could see the i2c timeout errors during suspend/resume, which
> makes the duration of suspend/resume too longer.
>
> [  484.171541] CPU4: Booted secondary processor [410fd082]
> [  485.172777] rk3x-i2c ff3c0000.i2c: timeout, ipd: 0x10, state: 1
> [  486.172760] rk3x-i2c ff3c0000.i2c: timeout, ipd: 0x10, state: 1
> [  487.172759] rk3x-i2c ff3c0000.i2c: timeout, ipd: 0x10, state: 1
> [  487.172840] cpu cpu4: _set_opp_voltage: failed to set voltage (800000
> 800000 800000 mV): -110
> [  487.172874] cpu cpu4: failed to set volt 800000
>
>>
>> I.e. I'd think the i2c-core does suspend i2c-client devices first, so that
>> these should be able to finish up their ongoing transfers and not start
>> any
>> new ones instead?
>>
>> Your irq can still happen slightly after the system started going to
>> actually
>> sleep, so to me it looks like you just widened the window where irqs can
>> be
>> handled. Especially as your irq could also just simply stem from the start
>> state, so you cannot even be sure if your transaction actually is
>> finished.
>
>
> Okay, you are right. I want to give it a double insurance at first, but it
> may hide the unhappend issue.
>
>>
>> So to me it looks like the i2c-connected device driver should be fixed
>> instead?
>
>
> I tell them to fix it in rk808 driver.

To me it seems like perhaps cpufreq should not be changing frequencies
until it is resumed properly.  Presumably if all the ordering is done
right then cpufreq should be resumed _after_ the i2c regulator so you
should be OK.  ...or am I somehow confused about that?

Also note that previous i2c busses I worked with simply returned -EIO
in the case where they were called when suspended.  See
"i2c-exynos5.c" and "i2c-s3c2410.c".

-Doug

Re: [PATCH] i2c: rk3x: keep i2c irq ON in suspend

[David.Wu]

Hi Doug,

在 2016/12/7 0:31, Doug Anderson 写道:
> Hi,
>
> On Tue, Dec 6, 2016 at 12:12 AM, David.Wu <david.wu@rock-chips.com> wrote:
>> Hi Heiko,
>>
>> 在 2016/12/5 18:54, Heiko Stuebner 写道:
>>>
>>> Hi David,
>>>
>>> Am Montag, 5. Dezember 2016, 16:02:59 CET schrieb David Wu:
>>>>
>>>> During suspend there may still be some i2c access happening.
>>>> And if we don't keep i2c irq ON, there may be i2c access timeout if
>>>> i2c is in irq mode of operation.
>>>
>>>
>>> can you describe the issue you're trying to fix a bit more please?
>>
>>
>> Sometimes we could see the i2c timeout errors during suspend/resume, which
>> makes the duration of suspend/resume too longer.
>>
>> [  484.171541] CPU4: Booted secondary processor [410fd082]
>> [  485.172777] rk3x-i2c ff3c0000.i2c: timeout, ipd: 0x10, state: 1
>> [  486.172760] rk3x-i2c ff3c0000.i2c: timeout, ipd: 0x10, state: 1
>> [  487.172759] rk3x-i2c ff3c0000.i2c: timeout, ipd: 0x10, state: 1
>> [  487.172840] cpu cpu4: _set_opp_voltage: failed to set voltage (800000
>> 800000 800000 mV): -110
>> [  487.172874] cpu cpu4: failed to set volt 800000
>>
>>>
>>> I.e. I'd think the i2c-core does suspend i2c-client devices first, so that
>>> these should be able to finish up their ongoing transfers and not start
>>> any
>>> new ones instead?
>>>
>>> Your irq can still happen slightly after the system started going to
>>> actually
>>> sleep, so to me it looks like you just widened the window where irqs can
>>> be
>>> handled. Especially as your irq could also just simply stem from the start
>>> state, so you cannot even be sure if your transaction actually is
>>> finished.
>>
>>
>> Okay, you are right. I want to give it a double insurance at first, but it
>> may hide the unhappend issue.
>>
>>>
>>> So to me it looks like the i2c-connected device driver should be fixed
>>> instead?
>>
>>
>> I tell them to fix it in rk808 driver.
>
> To me it seems like perhaps cpufreq should not be changing frequencies
> until it is resumed properly.  Presumably if all the ordering is done
> right then cpufreq should be resumed _after_ the i2c regulator so you
> should be OK.  ...or am I somehow confused about that?

yes，the cpufreq and regulator should start i2c job after they resume 
properly.

>
> Also note that previous i2c busses I worked with simply returned -EIO
> in the case where they were called when suspended.  See
> "i2c-exynos5.c" and "i2c-s3c2410.c".

In "i2c-exynos5.c", it seems that using the "i2c->suspended" to protect 
i2c transfer works most of the time. Of course it could prevent the next 
new i2c transfer to start. But in one case, if the current i2c job was 
not finished until the i2c irq was disabled by system suspend, the i2c 
timeout error would also happen, as the current i2c job may have a large 
data to transfer and it lasts from a long time.

So is it necessary to add a mutex lock to wait the current job to be 
finished before the "i2c->suspended" is changed in i2c_suspend_noirq()?

However, the i2c_suspend_noirq() is called after suspend_device_irqs() 
in system suspend, it means that the i2c timeout errors could happen 
during the time between suspend_device_irqs() and i2c_suspend_noirq(), 
if there were i2c transfers started.

>
> -Doug
>
>
>

Re: [PATCH] i2c: rk3x: keep i2c irq ON in suspend

[Grygorii Strashko]

On 12/06/2016 09:37 PM, David.Wu wrote:
> Hi Doug,
> 
> 在 2016/12/7 0:31, Doug Anderson 写道:
>> Hi,
>>
>> On Tue, Dec 6, 2016 at 12:12 AM, David.Wu <david.wu@rock-chips.com>
>> wrote:
>>> Hi Heiko,
>>>
>>> 在 2016/12/5 18:54, Heiko Stuebner 写道:
>>>>
>>>> Hi David,
>>>>
>>>> Am Montag, 5. Dezember 2016, 16:02:59 CET schrieb David Wu:
>>>>>
>>>>> During suspend there may still be some i2c access happening.
>>>>> And if we don't keep i2c irq ON, there may be i2c access timeout if
>>>>> i2c is in irq mode of operation.
>>>>
>>>>
>>>> can you describe the issue you're trying to fix a bit more please?
>>>
>>>
>>> Sometimes we could see the i2c timeout errors during suspend/resume,
>>> which
>>> makes the duration of suspend/resume too longer.
>>>
>>> [  484.171541] CPU4: Booted secondary processor [410fd082]
>>> [  485.172777] rk3x-i2c ff3c0000.i2c: timeout, ipd: 0x10, state: 1
>>> [  486.172760] rk3x-i2c ff3c0000.i2c: timeout, ipd: 0x10, state: 1
>>> [  487.172759] rk3x-i2c ff3c0000.i2c: timeout, ipd: 0x10, state: 1
>>> [  487.172840] cpu cpu4: _set_opp_voltage: failed to set voltage (800000
>>> 800000 800000 mV): -110
>>> [  487.172874] cpu cpu4: failed to set volt 800000
>>>
>>>>
>>>> I.e. I'd think the i2c-core does suspend i2c-client devices first,
>>>> so that
>>>> these should be able to finish up their ongoing transfers and not start
>>>> any
>>>> new ones instead?
>>>>
>>>> Your irq can still happen slightly after the system started going to
>>>> actually
>>>> sleep, so to me it looks like you just widened the window where irqs
>>>> can
>>>> be
>>>> handled. Especially as your irq could also just simply stem from the
>>>> start
>>>> state, so you cannot even be sure if your transaction actually is
>>>> finished.
>>>
>>>
>>> Okay, you are right. I want to give it a double insurance at first,
>>> but it
>>> may hide the unhappend issue.
>>>
>>>>
>>>> So to me it looks like the i2c-connected device driver should be fixed
>>>> instead?
>>>
>>>
>>> I tell them to fix it in rk808 driver.
>>
>> To me it seems like perhaps cpufreq should not be changing frequencies
>> until it is resumed properly.  Presumably if all the ordering is done
>> right then cpufreq should be resumed _after_ the i2c regulator so you
>> should be OK.  ...or am I somehow confused about that?
> 
> yes，the cpufreq and regulator should start i2c job after they resume
> properly.
> 
>>
>> Also note that previous i2c busses I worked with simply returned -EIO
>> in the case where they were called when suspended.  See
>> "i2c-exynos5.c" and "i2c-s3c2410.c".
> 
> In "i2c-exynos5.c", it seems that using the "i2c->suspended" to protect
> i2c transfer works most of the time. Of course it could prevent the next
> new i2c transfer to start. But in one case, if the current i2c job was
> not finished until the i2c irq was disabled by system suspend, the i2c
> timeout error would also happen, as the current i2c job may have a large
> data to transfer and it lasts from a long time.

And this means you have bug in some of I2C client drivers which do not stop
their activities during suspend properly (most usual case - driver uses work
and this work still active during suspend and can run on one CPU while suspend
runs on another).

At the moment .suspend_noirq() callback is called there should be no active
I2C transactions in general.

> 
> So is it necessary to add a mutex lock to wait the current job to be
> finished before the "i2c->suspended" is changed in i2c_suspend_noirq()?
> 

You need to catch and fix all driver who will try to access I2C after your
I2C bus driver passes suspend_noirq stage. Smth, like [1], uses i2c_lock_adapter().
 

[1] https://git.ti.com/android-sdk/kernel-omap/commit/125ef8f7016e7b205886f93862288a45a312b1d8

-- 
regards,
-grygorii

Re: [PATCH] i2c: rk3x: keep i2c irq ON in suspend

[David.Wu]

Hi Grygorii, Doug and Heiko,

Thanks for your replies.
I will do 2 steps:

1. Add "suspended" flag in suspend_noirq()/resume_noirq() callback to 
prevent new i2c started, and use i2c_lock_adapter() to wait for current 
i2c transfer finished.

2. IRQF_NO_SUSPEND added could make i2c work well during the time 
between suspend_device_irqs() and i2c_suspend_noirq() callback. In the 
other side, it is the the time between resume_device_irqs() and 
i2c_resume_noirq() callback.

If any i2c client try to access I2C after suspend_noirq() or before 
resume_noirq() callback, print the warning, and they should fix it, not 
to start i2c access and the moment.

在 2016/12/8 0:27, Grygorii Strashko 写道:
>
>
> On 12/06/2016 09:37 PM, David.Wu wrote:
>> Hi Doug,
>>
>> 在 2016/12/7 0:31, Doug Anderson 写道:
>>> Hi,
>>>
>>> On Tue, Dec 6, 2016 at 12:12 AM, David.Wu <david.wu@rock-chips.com>
>>> wrote:
>>>> Hi Heiko,
>>>>
>>>> 在 2016/12/5 18:54, Heiko Stuebner 写道:
>>>>>
>>>>> Hi David,
>>>>>
>>>>> Am Montag, 5. Dezember 2016, 16:02:59 CET schrieb David Wu:
>>>>>>
>>>>>> During suspend there may still be some i2c access happening.
>>>>>> And if we don't keep i2c irq ON, there may be i2c access timeout if
>>>>>> i2c is in irq mode of operation.
>>>>>
>>>>>
>>>>> can you describe the issue you're trying to fix a bit more please?
>>>>
>>>>
>>>> Sometimes we could see the i2c timeout errors during suspend/resume,
>>>> which
>>>> makes the duration of suspend/resume too longer.
>>>>
>>>> [  484.171541] CPU4: Booted secondary processor [410fd082]
>>>> [  485.172777] rk3x-i2c ff3c0000.i2c: timeout, ipd: 0x10, state: 1
>>>> [  486.172760] rk3x-i2c ff3c0000.i2c: timeout, ipd: 0x10, state: 1
>>>> [  487.172759] rk3x-i2c ff3c0000.i2c: timeout, ipd: 0x10, state: 1
>>>> [  487.172840] cpu cpu4: _set_opp_voltage: failed to set voltage (800000
>>>> 800000 800000 mV): -110
>>>> [  487.172874] cpu cpu4: failed to set volt 800000
>>>>
>>>>>
>>>>> I.e. I'd think the i2c-core does suspend i2c-client devices first,
>>>>> so that
>>>>> these should be able to finish up their ongoing transfers and not start
>>>>> any
>>>>> new ones instead?
>>>>>
>>>>> Your irq can still happen slightly after the system started going to
>>>>> actually
>>>>> sleep, so to me it looks like you just widened the window where irqs
>>>>> can
>>>>> be
>>>>> handled. Especially as your irq could also just simply stem from the
>>>>> start
>>>>> state, so you cannot even be sure if your transaction actually is
>>>>> finished.
>>>>
>>>>
>>>> Okay, you are right. I want to give it a double insurance at first,
>>>> but it
>>>> may hide the unhappend issue.
>>>>
>>>>>
>>>>> So to me it looks like the i2c-connected device driver should be fixed
>>>>> instead?
>>>>
>>>>
>>>> I tell them to fix it in rk808 driver.
>>>
>>> To me it seems like perhaps cpufreq should not be changing frequencies
>>> until it is resumed properly.  Presumably if all the ordering is done
>>> right then cpufreq should be resumed _after_ the i2c regulator so you
>>> should be OK.  ...or am I somehow confused about that?
>>
>> yes，the cpufreq and regulator should start i2c job after they resume
>> properly.
>>
>>>
>>> Also note that previous i2c busses I worked with simply returned -EIO
>>> in the case where they were called when suspended.  See
>>> "i2c-exynos5.c" and "i2c-s3c2410.c".
>>
>> In "i2c-exynos5.c", it seems that using the "i2c->suspended" to protect
>> i2c transfer works most of the time. Of course it could prevent the next
>> new i2c transfer to start. But in one case, if the current i2c job was
>> not finished until the i2c irq was disabled by system suspend, the i2c
>> timeout error would also happen, as the current i2c job may have a large
>> data to transfer and it lasts from a long time.
>
> And this means you have bug in some of I2C client drivers which do not stop
> their activities during suspend properly (most usual case - driver uses work
> and this work still active during suspend and can run on one CPU while suspend
> runs on another).
>
> At the moment .suspend_noirq() callback is called there should be no active
> I2C transactions in general.
>
>>
>> So is it necessary to add a mutex lock to wait the current job to be
>> finished before the "i2c->suspended" is changed in i2c_suspend_noirq()?
>>
>
> You need to catch and fix all driver who will try to access I2C after your
> I2C bus driver passes suspend_noirq stage. Smth, like [1], uses i2c_lock_adapter().
>
>
> [1] https://git.ti.com/android-sdk/kernel-omap/commit/125ef8f7016e7b205886f93862288a45a312b1d8
>