[PATCH] kernal: skip hpower setting for the module which has no revs

[照山周一郎]

Thanks for the advice.

This is a fix for a Japanese NTT OCU, which always outputs 2W, even
though the chip revision always returns 0. This is not a bug, but a
specification.
https://business.ntt-east.co.jp/service/onu/pdf/interface.pdf

Therefore, since the situation is too special to be handled by
sfp_module_parse_power(), the existing code was implemented to exit
the process in the process just before the error occurs.

The SF-8472 does not normally return 0, so there is no effect on other devices.
https://members.snia.org/document/dl/25916

If possible, I would appreciate some practical advice on compile-time warnings.

Translated with www.DeepL.com/Translator (free version)

2021年11月29日(月) 1:30 Bjørn Mork <bjorn at mork.no>:
>
> teruyama at springboard-inc.jp writes:
>
> > From: "S.Teruyama" <teruyama at springboard-inc.jp>
> >
> > Signed-off-by: S.Teruyama <teruyama at springboard-inc.jp>
> > ---
> >  .../pending-5.4/771-net-sfp-skip-hpowr-if-no-revision.patch  | 12 ++++++++++++
> >  1 file changed, 12 insertions(+)
> >  create mode 100644 target/linux/generic/pending-5.4/771-net-sfp-skip-hpowr-if-no-revision.patch
> >
> > diff --git a/target/linux/generic/pending-5.4/771-net-sfp-skip-hpowr-if-no-revision.patch b/target/linux/generic/pending-5.4/771-net-sfp-skip-hpowr-if-no-revision.patch
> > new file mode 100644
> > index 0000000..ffcf5ab
> > --- /dev/null
> > +++ b/target/linux/generic/pending-5.4/771-net-sfp-skip-hpowr-if-no-revision.patch
> > @@ -0,0 +1,12 @@
> > +@@ -0,0 +1,11 @@
> > +--- a/drivers/net/phy/sfp.c
> > ++++ b/drivers/net/phy/sfp.c
> > +@@ -1590,6 +1590,8 @@ static int sfp_module_parse_power(struct
> > +
> > + static int sfp_sm_mod_hpower(struct sfp *sfp, bool enable)
> > + {
> > ++    if (sfp->id.ext.sff8472_compliance == SFP_SFF8472_COMPLIANCE_NONE)
> > ++            return 0;
> > +     u8 val;
> > +     int err;
> > +
>
>
> This looks like a workaround for a specific buggy module.  Is that
> correct?   Why not update sfp_module_parse_power() instead so you can
> skip the HPOWER state completely?  And add an appropriate warning about
> this unexpected combination of options and sff8472_compliance.
>
>
> In any case, that "if" is misplaced. Your compiler should warn about it.
>
>
>
> Bjørn



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照山　周一郎
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