Hi,
Roger Quadros <rogerq@xxxxxx> writes:
>>> In host mode runtime suspend/resume could happen very often with
>>> device connected, and resetting h/w on every runtime_resume might not
>>> be desired. And PHYs drivers can also support runtime_suspend which
>>> would be preferred instead of shutting down phy.
>>
>> We don't do anything when dwc3 is working as a host, we simply assume if
>> we reach dwc3.ko, xhci has done its part. Here's what our
>> suspend_common looks like:
>>
>> static int dwc3_suspend_common(struct dwc3 *dwc)
>> {
>> unsigned long flags;
>>
>> switch (dwc->current_dr_role) {
>> case DWC3_GCTL_PRTCAP_DEVICE:
>> spin_lock_irqsave(&dwc->lock, flags);
>> dwc3_gadget_suspend(dwc);
>> spin_unlock_irqrestore(&dwc->lock, flags);
>> dwc3_core_exit(dwc);
>> break;
>> case DWC3_GCTL_PRTCAP_HOST:
>> default:
>> /* do nothing */
>> break;
>> }
>>
>> return 0;
>> }
>>
>> We're not resetting anything, not tearing down anything. No idea why
>> you're saying that in host mode we're breaking things apart. If you have
>> out-of-tree patches on top of v4.15-rc7, fix them instead of claiming
>> mainline is at fault.
>>
>
> This is the case after commit 689bf72c6e0d ("usb: dwc3: Don't
> reinitialize core during host bus-suspend/resume") which is breaking
> low power for TI platforms in Host mode.
>
> If we revert that commit we will be doing dwc3_core_exit() for host
> mode as well. Which is what we want for system suspend but probably
> not for runtime suspend in host case.
>
> This is why Manu wants to differentiate runtime vs system suspend.
We already differentiate them. Maybe the only thing we need is to *not*
call core_exit() in host-mode during runtime_suspend, but call it if
mode is device or during system sleep.
--
balbi
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