Messages in this thread | | | Date | Wed, 21 Sep 2016 14:18:45 -0500 | From | Bjorn Helgaas <> | Subject | Re: [PATCH V6 3/5] PCI: thunder-pem: Allow to probe PEM-specific register range for ACPI case |
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On Wed, Sep 21, 2016 at 11:58:22AM -0700, Duc Dang wrote: > On Wed, Sep 21, 2016 at 11:04 AM, Bjorn Helgaas <helgaas@kernel.org> wrote: > > On Wed, Sep 21, 2016 at 03:05:49PM +0100, Lorenzo Pieralisi wrote:
> > The existing x86 practice is to use PNP0C02 devices for this purpose, > > and I think we should just follow that practice. > > > > ... > > > > My point is that the hard-coding should not be buried in a driver > > where it's invisible to the rest of the kernel. If we hard-code it in > > a quirk that adds _CRS entries, then the kernel will work just like it > > would if the firmware had been correct in the first place. The > > resource will appear in /sys/devices/pnp*/*/resources and /proc/iomem, > > and if we ever used _SRS to assign or move ACPI devices, we would know > > to avoid the bridge resource. > > Are you suggesting to add code similar to functions in > linux/drivers/pnp/quirks.c to declare/attach the additional resource > that the host need to have when the resource is not in MCFG table?
Yes, but what I'm suggesting is actually a little stronger. This has nothing to do with whether a resource is in the MCFG table or not.
I'm suggesting ACPI firmware should always describe the resource. If the firmware is defective and doesn't describe it, we should add a quirk in pnp/quirks.c to add a resource for it.
Bjorn
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