Messages in this thread | | | Date | Tue, 10 Mar 2015 09:06:28 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH] x86: Bypass legacy PIC and PIT on ACPI hardware reduced platform |
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* Li, Aubrey <aubrey.li@linux.intel.com> wrote:
> >> - in x86_reduced_hw_init() set 'legacy_pic' to 'null_legacy_pic' > >> > >> - clean up 'global_clock_event' handling: instead of a global > >> variable, move its management into x86_platform_ops::get_clockevent() > >> and set the method to hpet/pit/abp/etc. specific handlers that > >> return the right clockevent device. > >> > >> - in your x86_reduced_hw_init() function add the hpet clockevent > >> device to x86_platform_ops::get_clockevent, overriding the default > >> PIT. > > how about this one? > > diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c > index b9e30da..70955d6 100644 > --- a/arch/x86/kernel/acpi/boot.c > +++ b/arch/x86/kernel/acpi/boot.c > @@ -1541,6 +1541,16 @@ int __init early_acpi_boot_init(void) > */ > early_acpi_process_madt(); > > + /* > + * Override x86_init functions and bypass legacy pic > + * in hardware-reduced ACPI mode > + */ > + if (acpi_gbl_reduced_hardware) { > + x86_init.timers.timer_init = x86_init_noop; > + x86_init.irqs.pre_vector_init = x86_init_noop; > + legacy_pic = &null_legacy_pic; > + }
Sounds good to me, assuming it builds, boots and works! :-)
A couple of extra suggestions:
1)
I'd suggest moving it into its own dedicated, appropriately named static function, to make it clear that 'ACPI Reduced Hardware' init happens there.
2)
I'd also initialize it like this:
x86_init.timers.timer_init = x86_init_noop; x86_init.irqs.pre_vector_init = x86_init_noop; legacy_pic = &null_legacy_pic;
to make the noop patterns stand out better.
3)
Once all is said and done, please also make acpi_gbl_reduced_hardware a flag internal to the ACPI code, not exposed to and used by other bits of x86 code.
> If the above makes sense, I'll send poweroff and reboot change > together in a seperate patch.
Yeah, please send them in a single series though, so they form a logical group.
Thanks,
Ingo
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