linux-kernel - Re: [PATCH v4 9/9] usb: dwc3: core: don't break during suspend/resume while we're dual-role

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Message-ID: <55E855A7.2010409@cogentembedded.com>
Date:	Thu, 3 Sep 2015 17:13:59 +0300
From:	Sergei Shtylyov <sergei.shtylyov@...entembedded.com>
To:	Roger Quadros <rogerq@...com>, balbi@...com
Cc:	tony@...mide.com, Joao.Pinto@...opsys.com,
	peter.chen@...escale.com, jun.li@...escale.com,
	linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-omap@...r.kernel.org
Subject: Re: [PATCH v4 9/9] usb: dwc3: core: don't break during suspend/resume
 while we're dual-role

On 09/03/2015 05:10 PM, Roger Quadros wrote:

>>>>> We can't rely just on dr_mode to decide if we're in host or gadget
>>>>> mode when we're configured as otg/dual-role. So while dr_mode is
>>>>> OTG, we find out from  the otg state machine if we're in host
>>>>> or gadget mode and take the necessary actions during suspend/resume.
>>>>>
>>>>> Also make sure that we disable OTG irq and events during system suspend
>>>>> so that we don't lockup the system during system suspend/resume.
>>>>>
>>>>> Signed-off-by: Roger Quadros <rogerq@...com>
>>>>> ---
>>>>>     drivers/usb/dwc3/core.c | 27 +++++++++------------------
>>>>>     1 file changed, 9 insertions(+), 18 deletions(-)
>>>>>
>>>>> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
>>>>> index 654aebf..25891e3 100644
>>>>> --- a/drivers/usb/dwc3/core.c
>>>>> +++ b/drivers/usb/dwc3/core.c
>>>>> @@ -1455,18 +1455,15 @@ static int dwc3_suspend(struct device *dev)
>>>>>             dwc->octl = dwc3_readl(dwc->regs, DWC3_OCTL);
>>>>>             dwc->oevt = dwc3_readl(dwc->regs, DWC3_OEVT);
>>>>>             dwc->oevten = dwc3_readl(dwc->regs, DWC3_OEVTEN);
>>>>> +        dwc3_writel(dwc->regs, DWC3_OEVTEN, 0);
>>>>> +        disable_irq(dwc->otg_irq);
>>>>>         }
>>>>>
>>>>> -    switch (dwc->dr_mode) {
>>>>> -    case USB_DR_MODE_PERIPHERAL:
>>>>> -    case USB_DR_MODE_OTG:
>>>>> +    if (dwc->dr_mode == USB_DR_MODE_PERIPHERAL ||
>>>>> +        ((dwc->dr_mode == USB_DR_MODE_OTG) && (dwc->fsm->protocol == PROTO_GADGET)))
>>>>
>>>>      Hm, you're not very consistent about your parens. :-)
>>>
>>> You're right. Should be
>>>
>>> if ((dwc->dr_mode == USB_DR_MODE_PERIPHERAL) ||
>>>       ((dwc->dr_mode == USB_DR_MODE_OTG) && (dwc->fsm->protocol == PROTO_GADGET)))
>>
>>     Parens around == are useless, I'd prefer if you deleted them. But if you'd like to keep them, let it be so. :-)

> OK, how about this then?

> if (dwc->dr_mode == USB_DR_MODE_PERIPHERAL ||
>      (dwc->dr_mode == USB_DR_MODE_OTG && dwc->fsm->protocol == PROTO_GADGET))

    Strictly speaking, parens around && are also not needed but gcc may 
probably issue a warning without them. Not sure, your call.

> cheers,
> -roger

MBR, Sergei

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