From: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
To: Rob Herring <robh@kernel.org>
Cc: "Z.q. Hou" <zhiqiang.hou@nxp.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
PCI <linux-pci@vger.kernel.org>,
Bjorn Helgaas <bhelgaas@google.com>,
Gustavo Pimentel <gustavo.pimentel@synopsys.com>,
Michael Walle <michael@walle.cc>,
Ard Biesheuvel <ardb@kernel.org>
Subject: Re: [PATCH] PCI: dwc: Added link up check in map_bus of dw_child_pcie_ops
Date: Tue, 20 Oct 2020 10:48:39 +0100 [thread overview]
Message-ID: <20201020094839.GA21935@e121166-lin.cambridge.arm.com> (raw)
In-Reply-To: <CAL_JsqLdQY_DqpduaTv4hMDM_-cvZ_+s8W+HdOuZVVYjTO4yxw@mail.gmail.com>
On Fri, Sep 18, 2020 at 09:27:40AM -0600, Rob Herring wrote:
[...]
> > > Maybe a link down just never happens once up, but if so, then we only need
> > > to check it once and fail probe.
> >
> > Many customers connect the FPGA Endpoint, which may establish PCIe link
> > after the PCIe enumeration and then rescan the PCIe bus, so I think it should
> > not exit the probe of root port even if there is not link up during enumeration.
>
> That's a good reason. I want to unify the behavior here as it varies
> per platform currently and wasn't sure which way to go.
We don't need to fail probe - just skip enumeration. Is there an IRQ
event associated with link coming up ? Scanning the bus can be done
upon link-up IRQ.
For platforms that forward the link down as an SError this still does
not solve the problem (if the link goes down unexpectedly) but I
question their design in the first place, this patch does not fix their
behaviour regardless.
Lorenzo
next prev parent reply other threads:[~2020-10-20 9:48 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-16 5:41 [PATCH] PCI: dwc: Added link up check in map_bus of dw_child_pcie_ops Zhiqiang Hou
2020-09-16 20:28 ` Rob Herring
2020-09-18 11:02 ` Z.q. Hou
2020-09-18 11:14 ` Michael Walle
2020-09-21 14:48 ` Z.q. Hou
2020-09-18 12:47 ` Bjorn Helgaas
2020-09-21 16:31 ` Z.q. Hou
2020-09-18 15:27 ` Rob Herring
2020-09-24 4:24 ` Z.q. Hou
2020-09-28 9:39 ` Lorenzo Pieralisi
2020-09-29 4:05 ` Z.q. Hou
2020-09-29 15:24 ` Gustavo Pimentel
2020-09-29 17:11 ` Rob Herring
2020-09-30 13:22 ` Kishon Vijay Abraham I
2020-09-30 15:01 ` Rob Herring
2020-10-01 13:32 ` Kishon Vijay Abraham I
2020-10-01 16:46 ` Michael Walle
2020-10-02 9:29 ` Naresh Kamboju
2020-10-08 14:46 ` Naresh Kamboju
2020-10-08 15:12 ` Rob Herring
2020-10-08 16:51 ` Naresh Kamboju
2020-10-08 15:08 ` Lorenzo Pieralisi
2020-10-12 16:31 ` Kishon Vijay Abraham I
2020-10-12 4:41 ` Z.q. Hou
2020-10-19 16:13 ` Lorenzo Pieralisi
2020-10-20 8:07 ` Kishon Vijay Abraham I
2020-10-12 4:22 ` Z.q. Hou
2020-10-20 9:48 ` Lorenzo Pieralisi [this message]
2020-10-13 9:15 ` Lorenzo Pieralisi
2020-10-14 11:13 ` Lorenzo Pieralisi
2020-10-14 12:37 ` Rob Herring
2020-10-15 22:47 ` Bjorn Helgaas
2020-10-16 11:59 ` Lorenzo Pieralisi
2020-10-19 5:24 ` Z.q. Hou
2020-10-19 5:41 ` Kishon Vijay Abraham I
2020-10-20 2:13 ` Z.q. Hou
2020-10-20 9:12 ` Lorenzo Pieralisi
2020-10-20 9:55 ` Lorenzo Pieralisi
2020-10-21 8:47 ` Z.q. Hou
2020-10-22 6:20 ` Richard Zhu
2020-10-19 16:26 ` Lorenzo Pieralisi
2020-10-20 10:19 ` Lorenzo Pieralisi
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