Messages in this thread | | | Subject | Re: [PATCH 1/5] misc: rtsx_usb: Use USB remote wakeup signaling for card insertion detection | From | Kai-Heng Feng <> | Date | Mon, 17 Sep 2018 16:07:27 +0800 |
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at 21:41, Alan Stern <stern@rowland.harvard.edu> wrote:
> On Thu, 13 Sep 2018, Kai-Heng Feng wrote: > >> I am working on the next version of this series, and the last missing >> puzzle is to differentiate system-wide resume from runtime resume in >> usb_driver's resume() and reset_resume() callback. >> >> The parent device, rtsx_usb, has two child devices, rtsx_usb_ms and >> rtsx_usb_sdmmc. >> pm_request_resume() is used in rtsx_usb's resume() to facilitate USB >> remote >> wakeup signaling, so we don't need to poll the card slot status. >> But this has a side effect: during system resume the rtsx_usb calls >> pm_request_resume() in its resume(), so child devices calls their >> runtime_resume() instead of resume() callback. > > Have you actually observed this? It shouldn't happen. > pm_request_resume() schedules a runtime resume on the PM work queue, > but this work queue is frozen during system sleep. It doesn't unfreeze > until after all the devices have been restored to full power. Thus the > child device's resume() callback should be invoked before > runtime_resume().
You are right, I read the trace wrong.
It happens right before system-wide suspension, when the PM core resumes it to fully functional state.
> >> So, is it reasonable to pass pm_message_t to resume() and reset_resume() >> callbacks and use PMSG_IS_AUTO() to differentiate them? > > It should not be necessary to do this.
Understood, thanks.
Kai-Heng
> > Alan Stern
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