linux-kernel - RE: [EXT] Re: [PATCH v1] usb: dwc3: remove the call trace of USBx

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Message-ID: <87h86nvtqo.fsf@gmail.com>
Date:   Mon, 12 Aug 2019 08:27:11 +0300
From:   Felipe Balbi <balbi@...nel.org>
To:     Yinbo Zhu <yinbo.zhu@....com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "linux-usb\@vger.kernel.org" <linux-usb@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>
Cc:     Xiaobo Xie <xiaobo.xie@....com>, Jiafei Pan <jiafei.pan@....com>,
        Ran Wang <ran.wang_1@....com>
Subject: RE: [EXT] Re: [PATCH v1] usb: dwc3: remove the call trace of USBx_GFLADJ


Hi,

Yinbo Zhu <yinbo.zhu@....com> writes:
>> > diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c index
>> > 98bce85c29d0..a133d8490322 100644
>> > --- a/drivers/usb/dwc3/core.c
>> > +++ b/drivers/usb/dwc3/core.c
>> > @@ -300,8 +300,7 @@ static void dwc3_frame_length_adjustment(struct
>> > dwc3 *dwc)
>> >
>> >       reg = dwc3_readl(dwc->regs, DWC3_GFLADJ);
>> >       dft = reg & DWC3_GFLADJ_30MHZ_MASK;
>> > -     if (!dev_WARN_ONCE(dwc->dev, dft == dwc->fladj,
>> > -         "request value same as default, ignoring\n")) {
>> > +     if (dft != dwc->fladj) {
>> 
>> if the value isn't different, why do you want to change it?
>> 
>> --
>> Balbi
> Hi Balbi,
>
> I don't change any value. I was remove that call trace.

Sure you do. The splat only shows when you request a FLADJ value that's
the same as the one already in the register. The reason you see the
splat is because your requested value is what's already in the HW.

So, again, why are you adding this device tree property if the value is
already the correct one?

> In addition that GFLADJ_30MHZ value intial value is 0, and it's value
> must be 0x20, if not, usb will not work.

it's not zero, otherwise the splat wouldn't trigger. You're requesting
the value that's already in your register by default.

-- 
balbi