acpi: New R/O 'hw.acpi.s4bios_supported' sysctl, gate S4BIOS with it
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Authored by olce on Fri, Jan 9, 5:09 PM.

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obiwac
jhb

Summary

As a safeguard, make sure that we won't try to enter S4 with the
firmware initiating machine state save if the ACPI implementation does
not indicate it as supported as per the standard (FACS present with bit
S4BIOS_F set).

This is also in preparation of probably switching the default for
'hw.acpi.s4bios' to false once OSPM-initiated S4 support is ready, in
which case administrators need some way to determine whether
firmware-initiated S4 support is possible. For now, we keep the same
default (set to true iff supported).

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Repository

rG FreeBSD src repository

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Build Status

Buildable 69770
Build 66653: arc lint + arc unit

Event Timeline

olce created this revision.Fri, Jan 9, 5:09 PM

Herald added a subscriber: imp. · View Herald TranscriptFri, Jan 9, 5:09 PM

olce requested review of this revision.Fri, Jan 9, 5:09 PM

Harbormaster completed remote builds in B69770: Diff 169409.Fri, Jan 9, 5:10 PM

olce added a parent revision: D54626: acpi: 'hw.acpi.s4bios' sysctl: Change type to bool, expand description.Fri, Jan 9, 5:10 PM

olce added a subscriber: emaste.Fri, Jan 9, 5:13 PM

Should we even allow hw.acpi.s4bios to be set if not supported? feels like it could be confusing to users not super familiar with power management that hw.acpi.s4bios is set but the system is not entering S4BIOS.