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linux/drivers/acpi/x86
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Rafael J. Wysocki 7edf6f7ef5 ACPI: PM: s2idle: Add module parameter for LPS0 constraints checking 
Commit 32ece31db4 ("ACPI: PM: s2idle: Only retrieve constraints when
needed") attempted to avoid useless evaluation of LPS0 _DSM Function 1
in lps0_device_attach() because pm_debug_messages_on might never be set
(and that is the case on production systems most of the time), but it
turns out that LPS0 _DSM Function 1 is generally problematic on some
platforms and causes suspend issues to occur when pm_debug_messages_on
is set now.

In Linux, LPS0 _DSM Function 1 is only useful for diagnostics and only
in the cases when the system does not reach the deepest platform idle
state during suspend-to-idle for some reason.  If such diagnostics is
not necessary, evaluating it is a loss of time, so using it along with
the other pm_debug_messages_on diagnostics is questionable because the
latter is expected to be suitable for collecting debug information even
during production use of system suspend.

For this reason, add a module parameter called check_lps0_constraints
to control whether or not the list of LPS0 constraints will be checked
in acpi_s2idle_prepare_late_lps0() and so whether or not to evaluate
LPS0 _DSM Function 1 (once) in acpi_s2idle_begin_lps0().

Fixes: 32ece31db4 ("ACPI: PM: s2idle: Only retrieve constraints when needed")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
Link: https://patch.msgid.link/2827214.mvXUDI8C0e@rafael.j.wysocki
History 2026-01-13 23:10:25 +01:00
..
apple.c ACPI: property: Support strings in Apple _DSM props 2023-04-27 18:50:26 +02:00
blacklist.c ACPI: x86: Move blacklist to x86 folder 2024-04-08 16:39:24 +02:00
cmos_rtc.c ACPI: x86: Move acpi_cmos_rtc to x86 folder 2024-04-08 16:39:24 +02:00
lpss.c ACPI: LPSS: Fix a spelling mistake 2025-11-27 14:08:26 +01:00
Makefile ACPI: x86: Move LPSS to x86 folder 2024-04-08 16:39:24 +02:00
s2idle.c ACPI: PM: s2idle: Add module parameter for LPS0 constraints checking 2026-01-13 23:10:25 +01:00
utils.c ACPI: x86: Extend Lenovo Yoga Tab 3 quirk with skip GPIO event-handlers 2025-03-27 20:41:19 +01:00