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From:   John Stultz <john.stultz@linaro.org>
Date:   Wed, 6 May 2020 15:27:40 -0700
Message-ID: <CALAqxLVXauXP0r4Hv2Axa4PNf_F9wp644peYV06bdsPtMKGmLA@mail.gmail.com>
Subject: Re: [PATCH v4 3/9] usb: dwc3: Increase timeout for CmdAct cleared by
 device controller
To:     Jun Li <lijun.kernel@gmail.com>
Cc:     Felipe Balbi <balbi@kernel.org>,
        lkml <linux-kernel@vger.kernel.org>,
        Yu Chen <chenyu56@huawei.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        ShuFan Lee <shufan_lee@richtek.com>,
        Heikki Krogerus <heikki.krogerus@linux.intel.com>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        Chunfeng Yun <chunfeng.yun@mediatek.com>,
        Hans de Goede <hdegoede@redhat.com>,
        Andy Shevchenko <andy.shevchenko@gmail.com>,
        Valentin Schneider <valentin.schneider@arm.com>,
        Jack Pham <jackp@codeaurora.org>,
        Linux USB List <linux-usb@vger.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>
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On Wed, May 6, 2020 at 2:00 AM Jun Li <lijun.kernel@gmail.com> wrote:
> John Stultz <john.stultz@linaro.org> =E4=BA=8E2019=E5=B9=B410=E6=9C=8830=
=E6=97=A5=E5=91=A8=E4=B8=89 =E4=B8=8A=E5=8D=885:18=E5=86=99=E9=81=93=EF=BC=
=9A
> > On Tue, Oct 29, 2019 at 2:11 AM Felipe Balbi <balbi@kernel.org> wrote:
> > > John Stultz <john.stultz@linaro.org> writes:
> > > > From: Yu Chen <chenyu56@huawei.com>
> > > >
> > > > It needs more time for the device controller to clear the CmdAct of
> > > > DEPCMD on Hisilicon Kirin Soc.
> > >
> > > Why does it need more time? Why is it so that no other platform needs
> > > more time, only this one? And which command, specifically, causes
> > > problem?
>
> Sorry for my back to this so late.
>
> This change is required on my dwc3 based HW too, I gave a check
> and the reason is suspend_clk is used in case the PIPE phy is at P3,
> this slow clock makes my EP command below timeout.
>
> dwc3_gadget_ep_cmd: ep0out: cmd 'Set Endpoint Configuration' [401]
> params 00001000 00000500 00000000 --> status: Timed Out
>
> Success case takes about 400us to complete, see below trace(44.286278
> - 44.285897 =3D 0.000381):
>
> configfs_acm.sh-822   [000] d..1    44.285896: dwc3_writel: addr
> 000000006d59aae1 value 00000401
> configfs_acm.sh-822   [000] d..1    44.285897: dwc3_readl: addr
> 000000006d59aae1 value 00000401
> ... ...
> configfs_acm.sh-822   [000] d..1    44.286278: dwc3_readl: addr
> 000000006d59aae1 value 00000001
> configfs_acm.sh-822   [000] d..1    44.286279: dwc3_gadget_ep_cmd:
> ep0out: cmd 'Set Endpoint Configuration' [401] params 00001000
> 00000500 00000000 --> status: Successful
>
> Hi John,
>
> Do you still have this problem? if yes, What's the value of
> USBLNKST[21:18] when the timeout happens?

Sorry. As I mentioned, I was working to upstream a patchset that I
hadn't created, so the context I had was limited. As I couldn't
reproduce an issue without the change on the device I had, I figured
it would be best to drop it.

However, as you have some analysis and rational for why such a change
would be needed, I don't have an objection to it. Do you want to
resubmit the patch with your explanation and detailed log above in the
commit message?

thanks
-john