[PATCH V2 0/3] ACPI,PCI,IRQ: revert penalty calculation for SCI

[Sinan Kaya]

Restoring the old behavior for IRQ < 256 and the dynamic penalty behavior
will remain effective for IRQ >= 256.

By the time ACPI gets initialized, this code tries to determine an
IRQ number based on penalty values in this array. It will try to locate
the IRQ with the least penalty assignment so that interrupt sharing is
avoided if possible.

A couple of notes about the external APIs:
1. These API can be called before the ACPI is started. Therefore, one
cannot assume that the PCI link objects are initialized for calculating
penalties.
2. The polarity and trigger information passed via the
acpi_penalize_sci_irq from the BIOS may not match what the IRQ subsystem
is reporting as the call might have been placed before the IRQ is
registered by the interrupt subsystem.

The reverted changes were in the direction to remove these external API and
try to calculate the penalties at runtime for the ISA, SCI as well as PCI
IRQS. This didn't work out well with the existing platforms.

Changes from V1 (https://lkml.org/lkml/2016/10/1/106):
* Commit message updates

Sinan Kaya (3):
  Revert "ACPI,PCI,IRQ: reduce static IRQ array size to 16"
  ACPI, PCI IRQ: add PCI_USING penalty for ISA interrupts
  Revert "ACPI,PCI,IRQ: remove SCI penalize function"

 arch/x86/kernel/acpi/boot.c |  1 +
 drivers/acpi/pci_link.c     | 71 ++++++++++++++++++++++-----------------------
 include/linux/acpi.h        |  1 +
 3 files changed, 37 insertions(+), 36 deletions(-)

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1.9.1