Re: [PATCH v2 1/2] x86/of: Add support for boot time interrupt delivery mode configuration

Andy Shevchenko
2022-11-16T10:54:12Z

On Wed, Nov 16, 2022 at 06:28:20PM +0800, Rahul Tanwar wrote:
> Presently, init/boot time interrupt delivery mode is enumerated
> only for ACPI enabled systems by parsing MADT table or for older
> systems by parsing MP table. But for OF based x86 systems, it is
> assumed & hardcoded to legacy PIC mode. This is a bug for
> platforms which are OF based but do not use 8259 compliant legacy
> PIC interrupt controller. Such platforms can not even boot because
> of this bug/hardcoding.
>
> Fix this bug by adding support for configuration of init time
> interrupt delivery mode for x86 OF based systems by introducing a
> new optional boolean property 'intel,virtual-wire-mode' for
> interrupt-controller node of local APIC. This property emulates
> IMCRP Bit 7 of MP feature info byte 2 of MP floating pointer
> structure [1].
>
> Defaults to legacy PIC mode if absent. Configures it to virtual
> wire compatibility mode if present.

> [1] https://www.manualslib.com/manual/77733/Intel-Multiprocessor.html?page=40#manual

Link: ?

...

> + if (of_property_read_bool(dn, "intel,virtual-wire-mode")) {

You need a separate patch to show this property being added (yes,
I have just commented on your patch 2).

> + printk(KERN_NOTICE "Virtual Wire compatibility mode.\n");
> + pic_mode = 0;
> + } else {
> + printk(KERN_NOTICE "IMCR and PIC compatibility mode.\n");
> + pic_mode = 1;

Why not pr_notice() in both cases?

> + }

--
With Best Regards,
Andy Shevchenko