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Commit32ece31db4("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