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From:   Avri Altman <Avri.Altman@wdc.com>
To:     "cang@codeaurora.org" <cang@codeaurora.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>
CC:     "asutoshd@codeaurora.org" <asutoshd@codeaurora.org>,
        "nguyenb@codeaurora.org" <nguyenb@codeaurora.org>,
        "rnayak@codeaurora.org" <rnayak@codeaurora.org>,
        "linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
        "kernel-team@android.com" <kernel-team@android.com>,
        "saravanak@google.com" <saravanak@google.com>,
        "salyzyn@google.com" <salyzyn@google.com>,
        Alim Akhtar <alim.akhtar@samsung.com>,
        Pedro Sousa <pedrom.sousa@synopsys.com>,
        "James E.J. Bottomley" <jejb@linux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        Evan Green <evgreen@chromium.org>,
        Kishon Vijay Abraham I <kishon@ti.com>,
        Stephen Boyd <swboyd@chromium.org>,
        Stanley Chu <stanley.chu@mediatek.com>,
        Vignesh Raghavendra <vigneshr@ti.com>,
        Bean Huo <beanhuo@micron.com>,
        Bart Van Assche <bvanassche@acm.org>,
        Venkat Gopalakrishnan <venkatg@codeaurora.org>,
        Tomas Winkler <tomas.winkler@intel.com>,
        Arnd Bergmann <arnd@arndb.de>,
        open list <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH v2 2/3] scsi: ufs: Modulize ufs-bsg
Thread-Topic: [PATCH v2 2/3] scsi: ufs: Modulize ufs-bsg
Thread-Index: AQHVr//eTRAsaCi7o0KCA+PFpTUx1Ke18FKAgAAc25KAAAI5UIAAw1gEgALB3gCAAT/UoA==
Date:   Sun, 15 Dec 2019 07:38:21 +0000
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=20
>=20
> On 2019-12-13 02:24, Bjorn Andersson wrote:
> > On Thu 12 Dec 08:53 PST 2019, cang@codeaurora.org wrote:
> >
> >> On 2019-12-12 15:00, Avri Altman wrote:
> >> > > On Wed 11 Dec 22:01 PST 2019, cang@codeaurora.org wrote:
> >> > > > On 2019-12-12 12:53, Bjorn Andersson wrote:
> >> > > > > On Wed 11 Dec 00:49 PST 2019, Can Guo wrote:
> > [..]
> >> > > > And in real cases, as the UFS is the boot device, UFS driver
> >> > > > will always be probed during bootup.
> >> > > >
> >> > >
> >> > > The UFS driver will load and probe because it's mentioned in the
> >> > > devicetree, but if either the ufs drivers or any of its
> >> > > dependencies (phy, resets, clocks, etc) are built as modules it
> >> > > might very well finish probing after lateinitcall.
> >> > >
> >> > > So in the even that the bsg is =3Dy and any of these drivers are
> >> > > =3Dm, or if you're having bad luck with your timing, the list will
> >> > > be empty.
> >> > >
> >> > > As described below, if bsg=3Dm, then there's nothing that will loa=
d
> >> > > the module and the bsg will not probe...
> >> > Right.
> >> > bsg=3Dy and ufshcd=3Dm is a bad idea, and should be avoided.
> >> >
> >>
> >> Yeah, I will get it addressed in the next patchset.
> >>
> >
> > If you build this around platform_device_register_data() from ufshcd I
> > don't see a reason to add additional restrictions on this combination
> > (even though it might not make much sense for people to use this
> > combination).
> >
> > Regards,
> > Bjorn
>=20
> Agree, thanks.
While at it, maybe you can add few words in the "BSG Support" paragraph,
In Documentation/scsi/ufs.txt.

Thanks,
Avri