[XS] Change in coreboot[main]: acpi/acpi_apic;arch/x86/acpi: better document ACPI_NO_PCAT_8259 case

[Felix Held (Code Review)]

Felix Held has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/82643?usp=email )

Change subject: acpi/acpi_apic;arch/x86/acpi: better document ACPI_NO_PCAT_8259 case
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acpi/acpi_apic;arch/x86/acpi: better document ACPI_NO_PCAT_8259 case

Both acpi_create_madt_sci_override and acpi_sci_int have special
handling for the ACPI_NO_PCAT_8259 case, but those cases weren't exactly
obvious, so add a comment with the reason for that.

Signed-off-by: Felix Held 
Change-Id: Ia6dcf59d5ab9226c61e9c4af95a73a07771b71d1
---
M src/acpi/acpi_apic.c
M src/arch/x86/acpi.c
2 files changed, 4 insertions(+), 1 deletion(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/43/82643/1

diff --git a/src/acpi/acpi_apic.c b/src/acpi/acpi_apic.c
index f367581..4b5b0fe 100644
--- a/src/acpi/acpi_apic.c
+++ b/src/acpi/acpi_apic.c
@@ -127,6 +127,8 @@

ioapic_get_sci_pin(&gsi, &irq, &flags);

+	/* In systems without 8259, the SCI_INT field in the FADT contains the SCI GSI number
+	   instead of the 8259 IRQ number */
    if (CONFIG(ACPI_NO_PCAT_8259))
    	irq = gsi;

diff --git a/src/arch/x86/acpi.c b/src/arch/x86/acpi.c
index bb61cd7..38efe13 100644
--- a/src/arch/x86/acpi.c
+++ b/src/arch/x86/acpi.c
@@ -12,7 +12,8 @@

ioapic_get_sci_pin(&gsi, &irq, &flags);

-	/* ACPI Release 6.5, 5.2.9 and 5.2.15.5. */
+	/* In systems without 8259, the SCI_INT field in the FADT contains the SCI GSI number
+	   instead of the 8259 IRQ number */
    if (CONFIG(ACPI_NO_PCAT_8259))
    	return gsi;