Messages in this thread | | | Date | Tue, 1 Mar 2022 11:13:30 +0000 | Subject | Re: [PATCH v3 3/3] soundwire: qcom: add in-band wake up interrupt support | From | Srinivas Kandagatla <> |
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On 28/02/2022 18:01, Pierre-Louis Bossart wrote: > >> @@ -1424,6 +1464,11 @@ static int swrm_runtime_resume(struct device *dev) >> struct qcom_swrm_ctrl *ctrl = dev_get_drvdata(dev); >> int ret; >> >> + if (ctrl->wake_irq > 0) { >> + if (!irqd_irq_disabled(irq_get_irq_data(ctrl->wake_irq))) >> + disable_irq_nosync(ctrl->wake_irq); >> + } >> + >> clk_prepare_enable(ctrl->hclk); > > This one is quite interesting. If you disable the IRQ mechanism but > haven't yet resumed the clock, that leaves a time window where the > peripheral could attempt to drive the line high. what happens in that case?
We did call pm_runtime_get_sync() from Wake IRQ handler, which means that resume should be finished as part of Wake IRQ handler. Any new Interrupt conditions/status generated by slave in the meantime will be cleared while handling SLAVE PEND interrupt.
> >> >> if (ctrl->clock_stop_not_supported) { >> @@ -1491,6 +1536,11 @@ static int __maybe_unused swrm_runtime_suspend(struct device *dev) >> >> usleep_range(300, 305); >> >> + if (ctrl->wake_irq > 0) { >> + if (irqd_irq_disabled(irq_get_irq_data(ctrl->wake_irq))) >> + enable_irq(ctrl->wake_irq); >> + } >> + > > and this one is similar, you could have a case where the peripheral > signals a wake immediately after the ClockStopNow frame, but you may not > yet have enabled the wake detection interrupt. > > Would that imply that the wake is missed? Its Possible it might be missed at that instance, however as the Slave interrupt source condition/status (Ex: button Press) is still not cleared it should generate a Wake interrupt as soon as its enabled.
--srini > > > >> return 0; >> } >>
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