Hi, Sinan,
On Tue, Sep 22, 2020 at 10:11 AM Huacai Chen <chenhc@xxxxxxxxxx> wrote:
>
> Hi, Sinan,
>
> On Mon, Sep 21, 2020 at 11:50 PM Sinan Kaya <okaya@xxxxxxxxxx> 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
>
> Huacai
