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From:   Felipe Balbi <balbi@kernel.org>
To:     Jun Li <lijun.kernel@gmail.com>,
        John Stultz <john.stultz@linaro.org>
Cc:     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>
Subject: Re: [PATCH v4 3/9] usb: dwc3: Increase timeout for CmdAct cleared by device controller
In-Reply-To: <CAKgpwJVU9m6G8PRdray2fGCp_peOU9C-ZAVKTk7pmSdq6z4NiA@mail.gmail.com>
References: <20191028215919.83697-1-john.stultz@linaro.org> <20191028215919.83697-4-john.stultz@linaro.org> <87mudjj4rc.fsf@gmail.com> <CALAqxLU+9uEcdRVaLfh+eQrDtZbDGod9pRXhBX=prAhg9MXagw@mail.gmail.com> <CAKgpwJVaKpsgMjKcnYyJsfNj0ibkPt=mdn-NxfOkeX1jfL=9iQ@mail.gmail.com> <CALAqxLVXauXP0r4Hv2Axa4PNf_F9wp644peYV06bdsPtMKGmLA@mail.gmail.com> <CAKgpwJU7VDx90STE7bhx9VZ5p1jtqCyyLavmhXfpaicyDAYt_g@mail.gmail.com> <CAKgpwJVU9m6G8PRdray2fGCp_peOU9C-ZAVKTk7pmSdq6z4NiA@mail.gmail.com>
Date:   Fri, 08 May 2020 15:35:23 +0300
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Hi,

Jun Li <lijun.kernel@gmail.com> writes:
> Jun Li <lijun.kernel@gmail.com> =E4=BA=8E2020=E5=B9=B45=E6=9C=887=E6=97=
=A5=E5=91=A8=E5=9B=9B =E4=B8=8A=E5=8D=8811:08=E5=86=99=E9=81=93=EF=BC=9A
>>
>> John Stultz <john.stultz@linaro.org> =E4=BA=8E2020=E5=B9=B45=E6=9C=887=
=E6=97=A5=E5=91=A8=E5=9B=9B =E4=B8=8A=E5=8D=886:27=E5=86=99=E9=81=93=EF=BC=
=9A
>> >
>> > 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> wr=
ote:
>> > > > > John Stultz <john.stultz@linaro.org> writes:
>> > > > > > From: Yu Chen <chenyu56@huawei.com>
>> > > > > >
>> > > > > > It needs more time for the device controller to clear the CmdA=
ct 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.
>>
>> That was fine.
>> >
>> > 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?
>>
>> Sure, I will resubmit the patch with my explanation added in commit mess=
age.
>
> Hi John
>
> A second think of this, I feel use readl_poll_timeout_atomic() to wait by=
 time
> is more proper here, so I create a new patch to address this also other
> registers polling, see below patch with you CCed:
>
> https://patchwork.kernel.org/patch/11536081/

Fixing a bug has nothing to do with using
readl_poll_timeout_atomic(). Please don't mix things as it just makes
review time consuming.

Let's find out what the bug is all about, only then should we consider
moving over to readl_poll_timeout_atomic().

=2D-=20
balbi

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