Re: [PATCH] PCI: Always set prefetchable base/limit upper32registers

From: Alex Williamson
Date: Mon Nov 30 2009 - 17:20:08 EST


On Mon, 2009-11-30 at 14:12 -0800, Yinghai Lu wrote:
> Alex Williamson wrote:
> > I don't believe the PCI spec dictates whether the upper 32bit base
> > should be 0 or -1, so it's purely a BIOS initialization choice and Linux
> > should properly handle both. If the hardware only supports 32bit
> > prefetchable windows, the hardware will drop the write, just as it did
> > for every 2.6 kernel before 1f82de10. Thanks,
>
> current code:
>
> #define PCI_PREF_RANGE_TYPE_MASK 0x0fUL
> #define PCI_PREF_RANGE_TYPE_32 0x00
> #define PCI_PREF_RANGE_TYPE_64 0x01
> #define PCI_PREF_RANGE_MASK (~0x0fUL)
>
> if the HW state the pref mmio is 64bit, we will touch upper 32bit. otherwise we will not touch it.

Really, where? Please paste the code that writes to
PCI_PREF_BASE_UPPER32 in the case of hardware supporting a 64bit
prefetchable window. I only see this happening if we are assigning it
to an IORESOURCE_MEM_64 resources.

Alex

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