Re: [PATCH v7 1/2] i2c: qcom-geni: Handle runtime PM disabled state during early resume

[Praveen Talari <praveen.talari@oss.qualcomm.com>]

Hi

On 23-07-2026 17:14, Mukesh Savaliya wrote:
>
>
> On 7/23/2026 4:24 PM, Praveen Talari wrote:
>> Hi mukesh
>>
>> On 23-07-2026 15:47, Mukesh Savaliya wrote:
>>> Hi Praveen,
>>>
>>> On 7/23/2026 3:32 PM, Praveen Talari wrote:
>>>> Hi Mukesh
>>>>
>>> [...]
>>>
>>>>> diff --git a/drivers/i2c/busses/i2c-qcom-geni.c b/drivers/i2c/ 
>>>>> busses/i2c-qcom-geni.c
>>>>> index 96dbf04138be..4bc00922cd97 100644
>>>>> --- a/drivers/i2c/busses/i2c-qcom-geni.c
>>>>> +++ b/drivers/i2c/busses/i2c-qcom-geni.c
>>>>> @@ -917,6 +917,10 @@ static int geni_i2c_xfer(struct i2c_adapter 
>>>>> *adap,
>>>>>       gi2c->err = 0;
>>>>>       reinit_completion(&gi2c->done);
>>>>>       ret = pm_runtime_get_sync(gi2c->se.dev);
>>>>> +    if (ret == -EACCES) {
>>>>> +        dev_warn(gi2c->se.dev, "Runtime PM is disabled:%d\n", ret);
>>>>> +        ret = 0;
>>>>
>>>> Here it is clear that pm_runtime_get_sync() is returning -EACCES 
>>>> from the runtime PM framework,
>>>>
>>>> which indicates that the request was rejected before the runtime 
>>>> resume path could enable any resources.
>>>>
>>>>  From the rpm_resume() implementation:
>>>>
>>>> static int rpm_resume(struct device *dev, int rpmflags) 
>>>> __releases(&dev-  >power.lock) __acquires(&dev->power.lock) { [...] 
>>>> repeat: if (dev-  >power.runtime_error) { retval = -EINVAL; } else 
>>>> if (dev-  >power.disable_depth > 0) { [...] else retval = -EACCES; 
>>>> } if (retval) goto out; [...] out: if (parent && 
>>>> !dev->power.irq_safe) { spin_unlock_irq(&dev->power.lock); 
>>>> pm_runtime_put(parent); spin_lock_irq(&dev->power.lock); } 
>>>> trace_rpm_return_int(dev, _THIS_IP_, retval); return retval; }
>>>>
>>>> The -EACCES error is returned when runtime PM is disabled 
>>>> (disable_depth  > 0),
>>>>
>>>> causing the function to exit without invoking the device's runtime 
>>>> resume callback.
>>>>
>>>> As a result, no resource enablement is performed by the PM framework.
>>>>
>>>>
>>>> In your change, the error is effectively converted to ret = 0 and 
>>>> execution continues.
>>>>
>>>> How can we guarantee that the required resources have been enabled 
>>>> in this scenario?
>>>>
>>>> More importantly, where are those resources expected to be enabled 
>>>> if the runtime PM resume path was never executed?
>>>>
>>>
>>> This was answered in V6 already on 7/3 exactly at same place.
>>> Pasting below.
>>>
>>> ==
>>> > Why we are checking specific error code here? Why can't we use the 
>>> below error check directly?
>>> > if get sync itself is failed with pm runtime disabled then why we 
>>> are going ahead by making ret = 0 here? How you will make sure 
>>> resources are enabled?
>>>
>>> This reason is also mentioned in the commit log. we surely get - 
>>> EACCESS as runtime PM is disabled during no_irq resume phase. We 
>>> still need to serve the transfer, hence we need to override it.
>>
>> We should not get it and not go further since you are already enabled 
>> in system_resume_no_irq().
>>
>> I just need to understand why we need to proceed when we get -EACCESS 
>> as runtime PM .
>>
>
> ret = 0 was added because during early system resume, -EACCES from 
> pm_runtime_get_sync() indicates runtime PM is disabled, not that the 
> controller is unusable; treating it as an error would incorrectly 
> reject valid I2C transfers occurring during resume.


What is the purpose of enabling runtime PM during system resume? It is 
not clear how this helps, given that -EACCES can still be returned.


>
> Other than early PM time, we are not going to get -EACESS. So i don't 
> see any case where this will be a problem.
>>>
>>> Review geni_i2c_resume_noirq() to know what all we do to enable 
>>> resources. That's guaranteed and tested with system suspend/resume 
>>> test back to back and PCIe could do i2c transfer successfully.
>>> ==
>>>>
>>>> Thanks,
>>>>
>>>> Praveen Talari
>>>>
>>> Do not keep this thanks/regards here. only leave the comments.
>>>
>>>>> +    }
>>> [...]
>