PNPACPI: compute Address Space length rather than using _LEN
ACPI _CRS Address Space Descriptors have _MIN, _MAX, and _LEN. Linux has
been computing Address Spaces as [_MIN to _MIN + _LEN - 1]. Based on the
tests in the bug reports below, Windows apparently uses [_MIN to _MAX].
Per spec (ACPI 4.0, Table 6-40), for _CRS fixed-size, fixed location
descriptors, "_LEN must be (_MAX - _MIN + 1)", and when that's true, it
doesn't matter which way we compute the end. But of course, there are
BIOSes that don't follow this rule, and we're better off if Linux handles
those exceptions the same way as Windows.
This patch makes Linux use [_MIN to _MAX], as Windows seems to do. This
effectively reverts 3162b6f0c5e and replaces it with simpler code.
https://bugzilla.kernel.org/show_bug.cgi?id=14337 (round)
https://bugzilla.kernel.org/show_bug.cgi?id=15480 (truncate)
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>
1 file changed