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From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
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Date: Mon, 6 Dec 2021 15:29:51 +0300
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Subject: ACPI: processor: idle: Only flush cache on entering C3
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Patch-mainline: v5.17-rc1
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Git-commit: 87ebbb8c612b1214f227ebb8f25442c6d163e802
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References: jsc#PED-1408
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According to ACPI 6.4, Section 8.2, CPU cache flushing required on
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entering the C3 power state.
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Avoid flushing the cache on entering other C-states.
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Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
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[ rjw: Changelog edits ]
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Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Acked-by: Lee, Chun-Yi <jlee@suse.com>
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---
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 drivers/acpi/processor_idle.c |    3 ++-
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 1 file changed, 2 insertions(+), 1 deletion(-)
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--- a/drivers/acpi/processor_idle.c
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+++ b/drivers/acpi/processor_idle.c
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@@ -565,7 +565,8 @@ static int acpi_idle_play_dead(struct cp
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 {
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 	struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);
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-	ACPI_FLUSH_CPU_CACHE();
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+	if (cx->type == ACPI_STATE_C3)
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+		ACPI_FLUSH_CPU_CACHE();
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 	while (1) {
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