Messages in this thread | | | Date | Sat, 16 Jul 2022 09:43:27 +0530 | Subject | Re: [PATCH v2] usb: dwc3: qcom: Defer dwc3-qcom probe if dwc3 isn't probed properly | From | Krishna Kurapati PSSNV <> |
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On 7/16/2022 2:11 AM, Matthias Kaehlcke wrote: > On Fri, Jul 15, 2022 at 06:51:52PM +0530, Krishna Kurapati wrote: > >> Subject: usb: dwc3: qcom: Defer dwc3-qcom probe if dwc3 isn't probed properly > nit: "isn't probed properly" sounds like a bug or HW issue. In case > you re-spin maybe change it to "hasn't probed yet" or similar. > >> On SC7180 devices, it is observed that dwc3 probing is deferred >> because device_links_check_suppliers() finds that '88e3000.phy' >> isn't ready yet. >> >> As a part of its probe call, dwc3-qcom driver checks if dwc3 core >> is wakeup capable or not. If the dwc3 core is wakeup capable, driver >> configures dwc-qcom's power domain to be always ON. Also it configures >> dp/dm interrupts accordingly to support wakeup from system suspend. >> >> More info regarding the same can be found at: >> commit d9be8d5c5b03 ("usb: dwc3: qcom: Keep power domain on to retain controller status") >> commit 6895ea55c385 ("usb: dwc3: qcom: Configure wakeup interrupts during suspend") >> >> In the event, dwc3 probe gets deferred and is processed after dwc3-qcom >> probe, driver ends up reading the wakeup capability of dwc3 core as false >> leading to instability in suspend/resume path. >> >> To avoid this scenario, ensure dwc3_probe is successful by checking >> if appropriate driver is assigned to it or not after the of_platform_populate >> call. If it isn't then defer dwc3-qcom probe as well. >> >> Fixes: 649f5c842ba3 ("usb: dwc3: core: Host wake up support from system suspend") >> Signed-off-by: Krishna Kurapati <quic_kriskura@quicinc.com> > Reported-by: Matthias Kaehlcke <mka@chromium.org> > Tested-by: Matthias Kaehlcke <mka@chromium.org> > Reviewed-by: Matthias Kaehlcke <mka@chromium.org> > > Please make sure to add reviewers of previous versions or other folks you > would like to review your patches in cc. I found v2 accidentally while > looking for something else. Hi Mathias, Sure, Thanks for the review.
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