-----Original Message----- From: devel-bounces(a)acpica.org [mailto:[email protected]] On Behalf Of Carter, Richard Sent: Friday, September 18, 2009 10:29 AM To: devel(a)acpica.org Subject: [Devel] MP configuration table construction I work for a commercial OS vendor. I've been asked to use ACPI to construct MP tables for some pentium boards that either lack a table or have errors in it. I have some questions and hope someone out in the community can answer them. As noted in the ACPI spec (par 5.2.11.7), should the MP table always have entries for the 16 ISA interrupts when dual-8259 support is indicated in the MADT? If dual-8259 support is not indicated, how do I determine which ISA interrupts are available? [Yakui]: Only the override interrupt entry is provided in MADT table. So when we construct the MP table by using ACPI MADT table, we should first use the Override interrupt entry to construct the ISA interrupts. Then the remaining ISA Interrupts are filled with the legacy setting. The PCI routing table reported by acpiGetIrqRoutingTable doesn't indicate interrupt level and triggering. Do PCI interrupts always conform to the bus specification or is there some other method for ACPI to report differences? [Yakui]: This depends on the returned value in _PRT table. If the following _PRT entry is returned, it uses the default PCI interrupt level/triggering. Package (0x04) { 0x001DFFFF, 0x01, 0x00, 0x15 }, If the following _PRT entry is returned, it uses the interrupt level/triggering parsed in The corresponding LINK device. Package (0x04) { 0xFFFF, 0x00, \_SB.PCI0.LNKA, 0x00 }, When there is more tha 1 IOAPIC, how does one determine which IOAPIC an interrupt reported by the _PRT belongs to? I see a GlobalIrqBase reported in the MADT IOAPIC record. Is this normally used to lookup which IOAPIC the IRQ is connected to? [Yakui]: Every IOAPIC has its own GSI interrupt base. When we get one GSI Number for one PCI device, we can use the GSI number to identify which IOAPIC is Used. For IRQ umber: We should first get the corresponding GSI number(This info can Be found in dmesg). And we can use the gsi number to find which IOAPIC is connected. Thanks. Thanks in advance Rich Carter 603-897-2071 _______________________________________________ Devel mailing list Devel(a)acpica.org http://lists.acpica.org/listinfo/devel