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SubjectRe: Switch APIC to driver model (and make S3 sleep with APIC on)
On Mon, 20 Jan 2003 23:25:27 +0100, Pavel Machek wrote:
>This switches apic code to driver model, cleans code up a lot, and
>makes S3 while apic is used work. Please apply,

Please don't apply this. It breaks stuff:

1. apic_suspend() unconditionally calls disable_apic_nmi_watchdog()
apic_resume() unconditionally calls setup_apic_nmi_watchdog()
apic_pm_state.perfctr_pmdev removed

- You're calling local-APIC NMI watchdog procedures even if
the local-APIC NMI watchdog isn't active. Bad.
- You're hardcoding that the local-APIC NMI watchdog is the
only possible sub-client of the local APIC. Not true.
- perfctr_pmdev exists precisely to handle both these cases
in a clean way.

2. You unconditionally register apic_driver with its suspend/resume
methods through a device_initcall().

This breaks if a UP_APIC or SMP kernel runs on a CPU with no or
an unusable local APIC. apic_pm_init2() does a runtime check
for successful init before doing a pm_register().

3. You severed the link between the PM API and the local APIC.

This breaks APM suspend when the local APIC is enabled. The
machine will hang (or immediately resume). I tested this, and
the driver model "stuff" simply doesn't do the right thing yet.

I you just want SOFTWARE_SUSPEND to work, why not simply post the
appropriate PM_SUSPEND and PM_RESUME events?
That should work without any changes to apic.c or nmi.c.

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