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In-Reply-To: <1cd5885d-7db4-59b9-ef2d-e3556f60ca68@st.com>
From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Fri, 14 Feb 2020 20:46:00 +0200
Message-ID: <CAHp75VcbPYNKfrnkuSfdN8t100kZFdq05hkbWxJKgRWJknRgxQ@mail.gmail.com>
Subject: Re: [PATCH] phy: core: Add consumer device link support
To:     Alexandre Torgue <alexandre.torgue@st.com>
Cc:     Kishon Vijay Abraham I <kishon@ti.com>,
        youling 257 <youling257@gmail.com>,
        Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        USB <linux-usb@vger.kernel.org>, saravanak@google.com
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On Mon, Feb 10, 2020 at 1:32 PM Alexandre Torgue
<alexandre.torgue@st.com> wrote:
> On 2/10/20 9:08 AM, Kishon Vijay Abraham I wrote:
> > On 07/02/20 12:27 PM, youling 257 wrote:
> >> test this diff, dwc3 work for my device, thanks.
> >>
> >> 2020-02-07 13:16 GMT+08:00, Kishon Vijay Abraham I <kishon@ti.com>:
> >>> On 06/02/20 7:09 PM, youling257 wrote:
> >>>> This patch cause "dwc3 dwc3.3.auto: failed to create device link to
> >>>> dwc3.3.auto.ulpi" problem.
> >>>> https://bugzilla.kernel.org/show_bug.cgi?id=206435

+1 to the report.
Please revert for v5.6 or provide a fix ASAP!

> >>>
> >>> I'm suspecting there is some sort of reverse dependency with dwc3 ULPI.
> >>> Can you try the following diff?
> >>>
> >>> diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
> >>> index 2eb28cc2d2dc..397311dcb116 100644
> >>> --- a/drivers/phy/phy-core.c
> >>> +++ b/drivers/phy/phy-core.c
> >>> @@ -687,7 +687,7 @@ struct phy *phy_get(struct device *dev, const char
> >>> *string)
> >>>
> >>>          get_device(&phy->dev);
> >>>
> >>> -       link = device_link_add(dev, &phy->dev, DL_FLAG_STATELESS);
> >>> +       link = device_link_add(dev, &phy->dev, DL_FLAG_SYNC_STATE_ONLY);
> >>>          if (!link) {
> >>>                  dev_err(dev, "failed to create device link to %s\n",
> >>>                          dev_name(phy->dev.parent));
> >>> @@ -802,7 +802,7 @@ struct phy *devm_of_phy_get(struct device *dev,
> >>> struct device_node *np,
> >>>                  return phy;
> >>>          }
> >>>
> >>> -       link = device_link_add(dev, &phy->dev, DL_FLAG_STATELESS);
> >>> +       link = device_link_add(dev, &phy->dev, DL_FLAG_SYNC_STATE_ONLY);
> >>>          if (!link) {
> >>>                  dev_err(dev, "failed to create device link to %s\n",
> >>>                          dev_name(phy->dev.parent));
> >>> @@ -851,7 +851,7 @@ struct phy *devm_of_phy_get_by_index(struct device
> >>> *dev, struct device_node *np,
> >>>          *ptr = phy;
> >>>          devres_add(dev, ptr);
> >>>
> >>> -       link = device_link_add(dev, &phy->dev, DL_FLAG_STATELESS);
> >>> +       link = device_link_add(dev, &phy->dev, DL_FLAG_SYNC_STATE_ONLY);
> >>>          if (!link) {
> >>>                  dev_err(dev, "failed to create device link to %s\n",
> >>>                          dev_name(phy->dev.parent));Parent
> >
> > Can you check if this doesn't affect the suspend/resume ordering?
>
> With this fix, suspend/resume ordering is broken on my side. What do you
> think to keep the STATELESS flag and to only display a warn if
> "device_link_add" returns an error ? It's not "smart" but it could
> solved our issue.
>
> As a lot of improvements have been recently done on device link topic by
> Saravana, we could check with him what is the way to follow.
>
> Regards
> Alex
>
> >
> > Thanks
> > Kishon
> >


-- 
With Best Regards,
Andy Shevchenko