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References: <20220622040924.113279-1-mie@igel.co.jp> <20220705224028.GA90560@bhelgaas>
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From:   Shunsuke Mie <mie@igel.co.jp>
Date:   Wed, 6 Jul 2022 11:37:29 +0900
Message-ID: <CANXvt5qjx6gXhBZD3ndBPCxx++i2oxd5X7=MRgUGrXUj4kRgfw@mail.gmail.com>
Subject: Re: [PATCH] PCI: endpoint: Don't stop EP controller by EP function
To:     Bjorn Helgaas <helgaas@kernel.org>
Cc:     Kishon Vijay Abraham I <kishon@ti.com>,
        Lorenzo Pieralisi <lpieralisi@kernel.org>,
        =?UTF-8?Q?Krzysztof_Wilczy=C5=84ski?= <kw@linux.com>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Hou Zhiqiang <Zhiqiang.Hou@nxp.com>,
        Li Chen <lchen@ambarella.com>, linux-pci@vger.kernel.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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2022=E5=B9=B47=E6=9C=886=E6=97=A5(=E6=B0=B4) 7:40 Bjorn Helgaas <helgaas@ke=
rnel.org>:

>
> On Wed, Jun 22, 2022 at 01:09:24PM +0900, Shunsuke Mie wrote:
> > For multi-function endpoint device, an ep function shouldn't stop EP
> > controller. Nomally the controller is stopped via configfs.
>
> Can you please clarify this for me?
>
> An endpoint function by itself wouldn't stop an endpoint controller.
> I assume that some *operation* on an endpoint function currently stops
> the endpoint controller, but that operation should not stop the
> controller?
>
> I guess the operation is an "unbind" that detaches an EPF device from
> an EPC device?
It is likely that after all of the endpoint functions are unbound, the
controller can be stopped safely, but I'm not sure if it is desired behavio=
r
for endpoint framework.

Kishon, could you please comment?

> > Fixes: 349e7a85b25f ("PCI: endpoint: functions: Add an EP function to t=
est PCI")
> > Signed-off-by: Shunsuke Mie <mie@igel.co.jp>
> > ---
> >  drivers/pci/endpoint/functions/pci-epf-test.c | 1 -
> >  1 file changed, 1 deletion(-)
> >
> > diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pc=
i/endpoint/functions/pci-epf-test.c
> > index 5b833f00e980..a5ed779b0a51 100644
> > --- a/drivers/pci/endpoint/functions/pci-epf-test.c
> > +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
> > @@ -627,7 +627,6 @@ static void pci_epf_test_unbind(struct pci_epf *epf=
)
> >
> >       cancel_delayed_work(&epf_test->cmd_handler);
> >       pci_epf_test_clean_dma_chan(epf_test);
> > -     pci_epc_stop(epc);
> >       for (bar =3D 0; bar < PCI_STD_NUM_BARS; bar++) {
> >               epf_bar =3D &epf->bar[bar];
> >
> > --
> > 2.17.1
> >

Thanks,
Shunsuke