These patches simplify the way we handle Address Space descriptors and make
Linux do it more like Windows does.
The PNPACPI change is definitely .35 material, since I don't think anybody
uses this information via PNP yet.
My first thought was that the x86/PCI change is for .35, too, but it does
make a difference in some cases, so maybe it should go in .34.
Here's an example where it matters. ACPI _CRS could have an MMIO Address Space
descriptor like this:
_MIN 0xE0000000
_MAX 0xFEBFFFFF
_LEN 0x10000000,
which doesn't satisfy the spec requirement that:
_MAX == _MIN + _LEN - 1,
but obviously we can't rely on spec compliance. These are the ways we could
interpret it:
[mem 0xe0000000-0xefffffff] current Linux way (end is _MIN + _LEN - 1)
[mem 0xe0000000-0xfebfffff] new Linux way (end is _MAX)
[mem 0xe0000000-0xfebfffff] Windows way (end is _MAX)
The risk is that BIOS might have placed a PCI device in the area that we used
to think was illegal, i.e., anywhere in [mem 0xf0000000-0xfebfffff], and Linux
will try to move the device unnecessarily, and that move might fail.
---
Bjorn Helgaas (2):
PNPACPI: compute Address Space length rather than using _LEN
x86/PCI: compute Address Space length rather than using _LEN
arch/x86/pci/acpi.c | 40 ++--------------------------------------
drivers/pnp/pnpacpi/rsparser.c | 26 ++++----------------------
2 files changed, 6 insertions(+), 60 deletions(-)
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