Re: [PATCH 1/2] usb: dwc3: support continuous runtime PM with dual role

[Martin Kepplinger]

On 18.03.20 12:13, Roger Quadros wrote:
> Martin,
> 
> On 18/03/2020 10:35, Martin Kepplinger wrote:
>> The DRD module calls dwc3_set_mode() on role switches, i.e. when a
>> device is
>> being pugged in. In order to support continuous runtime power
>> management when
>> plugging in / unplugging a cable, we need to call pm_runtime_get() in
>> this path.
>>
>> Signed-off-by: Martin Kepplinger <martin.kepplinger@xxxxxxx>
>> ---
>> Â drivers/usb/dwc3/core.c | 5 +++++
>> Â 1 file changed, 5 insertions(+)
>>
>> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
>> index edc17155cb2b..7743c4de82e9 100644
>> --- a/drivers/usb/dwc3/core.c
>> +++ b/drivers/usb/dwc3/core.c
>> @@ -196,11 +196,16 @@ void dwc3_set_mode(struct dwc3 *dwc, u32 mode)
>> Â {
>> ÂÂÂÂÂ unsigned long flags;
>> Â +ÂÂÂ pm_runtime_get(dwc->dev);
>> +
>> ÂÂÂÂÂ spin_lock_irqsave(&dwc->lock, flags);
>> ÂÂÂÂÂ dwc->desired_dr_role = mode;
>> ÂÂÂÂÂ spin_unlock_irqrestore(&dwc->lock, flags);
>> Â ÂÂÂÂÂ queue_work(system_freezable_wq, &dwc->drd_work);
> 
> We are not touching any IP registers and just scheduling
> the drd_work in this function so it doesn't make sense to do
> pm_runtime_get here.
> 
> How about dong pm_runtime_get/put in __dwc3_set_mode()?

That would be more accurate indeed. I'll move it over there. thanks for
having a look!

                           martin


> 
>> +
>> +ÂÂÂ pm_runtime_mark_last_busy(dwc->dev);
>> +ÂÂÂ pm_runtime_put_autosuspend(dwc->dev);
>> Â }
>> Â Â u32 dwc3_core_fifo_space(struct dwc3_ep *dep, u8 type)
>>
>