On 09/26/2018 11:23 AM, Tony Lindgren wrote:
> * Tony Lindgren <tony@xxxxxxxxxxx> [180926 16:04]:
>> * Keerthy <j-keerthy@xxxxxx> [180926 04:12]:
>>> So the below patch is solving the problem only for the first iteration
>>> but i see the problem recurring from second iteration of suspend.
>>>
>>> I tried the above cycle multiple times on am437x-gp-evm. I believe
>>> we are one step closer still not completely fixed.
>>
>> OK thanks, that's interesting, I'll take a look. Good to hear
>> that is the reason for pixcir issues though :)
>
> Heh ooops the previous i2c-omap patch I posted does unpaired
> runtime_pm calls.. The put must be left out omap_i2c_resume().
>
> Below is a better patch, seems to work for me multiple times
> now.
>
> Regards,
>
> Tony
>
> 8< ---------------------------
> diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
> --- a/drivers/i2c/busses/i2c-omap.c
> +++ b/drivers/i2c/busses/i2c-omap.c
> @@ -208,6 +208,8 @@ struct omap_i2c_dev {
> * if set, should be trsh+1
> */
> u32 rev;
> + unsigned int is_suspended:1;
> + unsigned int needs_resume:1;
> unsigned b_hw:1; /* bad h/w fixes */
> unsigned bb_valid:1; /* true when BB-bit reflects
> * the I2C bus state
> @@ -1498,8 +1500,7 @@ static int omap_i2c_remove(struct platform_device *pdev)
> return 0;
> }
>
> -#ifdef CONFIG_PM
> -static int omap_i2c_runtime_suspend(struct device *dev)
> +static int __maybe_unused omap_i2c_runtime_suspend(struct device *dev)
> {
> struct omap_i2c_dev *omap = dev_get_drvdata(dev);
>
> @@ -1521,11 +1522,12 @@ static int omap_i2c_runtime_suspend(struct device *dev)
> }
>
> pinctrl_pm_select_sleep_state(dev);
> + omap->is_suspended = true;
>
> return 0;
> }
>
> -static int omap_i2c_runtime_resume(struct device *dev)
> +static int __maybe_unused omap_i2c_runtime_resume(struct device *dev)
> {
> struct omap_i2c_dev *omap = dev_get_drvdata(dev);
>
> @@ -1535,6 +1537,51 @@ static int omap_i2c_runtime_resume(struct device *dev)
> return 0;
>
> __omap_i2c_init(omap);
> + omap->is_suspended = false;
> +
> + return 0;
> +}
> +
> +static int __maybe_unused omap_i2c_suspend(struct device *dev)
> +{
> + struct omap_i2c_dev *ddata = dev_get_drvdata(dev);
> + int error;
> +
> + /* Is device still enabled because of autosuspend? */
> + if (ddata->is_suspended)
> + return 0;
Sry, but you can't do this. There is no sync between suspend and PM runtime.
> +
> + /* Paired with call in omap_i2c_resume() */
> + error = pm_runtime_put_sync_suspend(dev);
This is nop!!! More over, in general you can't predict how many times pm_runtime_get was called and
what's the current value of usage_count.
> + if (error < 0) {
> + dev_err(dev, "%s failed: %i\n", __func__, error);
> +
> + return error;
> + }
> +
> + ddata->needs_resume = true;
> +
> + return 0;
> +}
> +
> +static int __maybe_unused omap_i2c_resume(struct device *dev)
> +{
> + struct omap_i2c_dev *ddata = dev_get_drvdata(dev);
> + int error;
> +
> + if (!ddata->needs_resume)
> + return 0;
> +
> + /* Paired with call in omap_i2c_suspend() */
> + error = pm_runtime_get_sync(dev);
> + if (error < 0) {
> + dev_err(dev, "%s failed: %i\n", __func__, error);
> + pm_runtime_put_noidle(dev);
> +
> + return error;
> + }
> +
> + ddata->needs_resume = false;
>
> return 0;
> }
To make things work the pm_runtime_force_xx() have to be used, or
like with omap_device, platform/bus code have to handle device state
at suspend_no_irq stage.
1) dev A :.suspend() - device is in active state (PM runtime)
- .suspend_noirq() - platform/bus/pm_domain - disable device and mark for resume
- .resume_noirq() - platform/bus/pm_domain - enable device and clear mark
- .resume() - device in active state
2) dev A :.suspend() device is in suspended state and nothing to do
.suspend_noirq() - platform/bus/pm_domain - nop
.resume_noirq() - platform/bus/pm_domain - nop
.resume() - device in suspended state. if smth need to be done - pm_runtime_get() have to be called
3) dev A :.suspend() device is in suspended state and dev A must be prepared for suspend
-- pm_runtime_get()
-- prepare dev A for suspend
- .suspend_noirq() - platform/bus/pm_domain - disable device and mark for resume
- .resume_noirq() - platform/bus/pm_domain - enable device and clear mark
- .resume() - device in active state.
-- resume dev A
-- pm_runtime_put()
4) dev A :.suspend() device is in suspended state and dev A must be prepared for suspend
-- pm_runtime_get()
-- prepare dev A for suspend
-- pm_runtime_put() <-- dev will not be disabled just usage usage_count sync.
- .suspend_noirq() - platform/bus/pm_domain - disable device and mark for resume
- .resume_noirq() - platform/bus/pm_domain - enable device and clear mark
- .resume() - nothing to do
- .complete() : device_complete()->pm_runtime_put() will disable device
--
regards,
-grygorii
