Re: [PATCH] phy: core: Add consumer device link support

[Alexandre Torgue <alexandre.torgue@xxxxxx>]

Hi Kishon,

On 2/10/20 9:08 AM, Kishon Vijay Abraham I wrote:
> Hi Alexandre,
>
> 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@xxxxxx>:
> > > Hi,
> > >
> > > 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
> > >
> > > 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