On Sun, Jun 25, 2023 at 12:01:12PM +0800, Guiting Shen wrote: > On Fri, Jun 23, 2023 at 23:52:53PM GMT+8, Alan Stern wrote: > >> The comment which was added with commit-id 0365ee0a8f745 may be outdated > >> because ohci_suspend() and ohci_at91_port_suspend() is used to suspend > >> instead of setting ohci->rh_state to OHCI_RH_HALTED. > > > > The comment says nothing about ohci->rh_state; it talks about the > > integrated transceivers and the 48 MHz clock. I don't see why you would > > think the comment is outdated. > > > > The comment says the reason to discard connection state by reset, but I > don't see any reset operation at ohci-at91 suspend/resume routine in > source code.And ohci_suspend() disable irq emission and mark HW > unaccessible maybe do the same effect as set ohci->rh_state to > OHCI_RH_HALTED to discard connection state which I think the comment is > outdated. No, it doesn't do the same. An actual reset is needed. > >> What's more, I found that only ohci-at91 driver to set the ohci->rh_state > >> which may be unnessory because the ohci_suspend() disable irq emission and > >> mark HW unaccessible and ohci_at91_port_suspend() suspend the controller. > >> > >> Is it really need to set ohci->rh_state in ohci_hcd_at91_drv_suspend()? > >> > >> It maybe confused to set ohci->rh_state to OHCI_RH_SUSPEND in resume > >> routine. > > > > I'm not really sure what that assignment was intended to accomplish, but > > maybe it was meant to force a reset when the controller resumes. > > > > You could get the same result by leaving ohci->rh_state set to > > OHCI_RH_SUSPENDED but changing ohci_hcd_at91_drv_resume(). Instead of > > calling ohci_resume(hcd, false), have it call: > > > > ohci_resume(hcd, !ohci_at91->wakeup); > > > > That way, if the wakeup flag is clear and the clock was stopped, > > ohci_resume() will call ohci_usb_reset(). You should also add a comment > > explaining the reason. > > > > I can't test this because I don't have the AT91 hardware. > > > > It works by your methods to force a reset in my sama5d3 soc hardware. > And I found that the ohci->rh_state was already OHCI_RH_SUSPEND before > set it OHCI_RH_HALTED in suspend.So the question is whether to set it > OHCI_RH_HALETED in ohci-at91 suspend routine. > > It also works by comment the ohci->rh_state = OHCI_RH_HALTED in suspend > routine.But I think it is safer to use your methods. > > Do you have any suggestion on it before I send v2 patch latter. No suggestions now. Submit your v2 patch and then maybe I'll have something more to say. Alan Stern
