From: Huacai Chen <chenhuacai@gmail.com>
To: Sinan Kaya <okaya@kernel.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
linux-pci <linux-pci@vger.kernel.org>,
Jiaxun Yang <jiaxun.yang@flygoat.com>,
Tiezhu Yang <yangtiezhu@loongson.cn>
Subject: Re: [PATCH] PCI/portdrv: Don't disable pci device during shutdown
Date: Thu, 31 Dec 2020 14:15:17 +0800 [thread overview]
Message-ID: <CAAhV-H5SDrOUO-BdptM=e-VwOBrVQ+UtqxVx+qYNU2FO12w+SQ@mail.gmail.com> (raw)
In-Reply-To: <CAAhV-H6_BBe1MWJyuVrQNd7NyOarUtz1_YKrQJYxXs3Jby-bsw@mail.gmail.com>
Hi, Bjorn
On Tue, Sep 22, 2020 at 2:16 PM Huacai Chen <chenhuacai@gmail.com> wrote:
>
> Hi, Sinan,
>
> On Tue, Sep 22, 2020 at 10:11 AM Huacai Chen <chenhc@lemote.com> wrote:
> >
> > Hi, Sinan,
> >
> > On Mon, Sep 21, 2020 at 11:50 PM Sinan Kaya <okaya@kernel.org> wrote:
> > >
> > > On 9/21/2020 5:22 AM, Huacai Chen wrote:
> > > > Use separate remove()/shutdown() callback, and don't disable pci device
> > > > during shutdown. This can avoid some poweroff/reboot failures.
> > > >
> > > > The poweroff/reboot failures can easily reproduce on Loongson platforms.
> > > > I think this is not a Loongson-specific problem, instead, is a problem
> > > > related to some specific PCI hosts. On some x86 platforms, radeon/amdgpu
> > > > devices can cause the same problem, and commit faefba95c9e8ca3a523831c2e
> > > > ("drm/amdgpu: just suspend the hw on pci shutdown") can resolve it.
> > >
> > > This sounds like a quirk to me rather than a behavior that should be
> > > applied to all platforms.
> > Yes, this is very like a quirk, but it seems there are a lot of
> > platforms that have problems, and removing the pci_disable_device()
> > has no side effect.
> I have seen that you talk about kexec (but this email didn't go to my
> inbox). This has been discussed in another thread, and Lucas told us
> that in pci_device_shutdown the Bus Master is disabled for kexec. So I
> think there will be no memory corruption. Moreover, before 4.15 there
> is no .shutdown callback for portdrv, but kexec still works.
>
> Yes, the perfect way is to modify all problematic drivers, as
> radeon/amdgpu does. But I don't have enough knowledge about all of the
> devices.
>
> Huacai
Any new comments?
Huacai
> >
> > Huacai
prev parent reply other threads:[~2020-12-31 6:16 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-21 9:22 [PATCH] PCI/portdrv: Don't disable pci device during shutdown Huacai Chen
2020-09-21 15:50 ` Sinan Kaya
2020-09-22 2:11 ` Huacai Chen
2020-09-22 4:30 ` Sinan Kaya
2020-09-22 6:20 ` Tiezhu Yang
2020-09-22 6:16 ` Huacai Chen
2020-12-31 6:15 ` Huacai Chen [this message]
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