From b208d1915f1bdba93678b51b87ae214d9e2ca7a3 Mon Sep 17 00:00:00 2001 From: Bin Meng Date: Fri, 21 Apr 2017 07:24:42 -0700 Subject: [PATCH] x86: apci: Change PM1_CNT register access to RMW In enter_acpi_mode() PM1_CNT register is changed to PM1_CNT_SCI_EN directly without preserving its previous value. Update to change the register access to read-modify-write (RMW). Signed-off-by: Bin Meng Reviewed-by: Simon Glass Tested-by: Stefan Roese --- arch/x86/lib/acpi_table.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/x86/lib/acpi_table.c b/arch/x86/lib/acpi_table.c index f1183452f8..8be8120e3d 100644 --- a/arch/x86/lib/acpi_table.c +++ b/arch/x86/lib/acpi_table.c @@ -306,6 +306,8 @@ static void acpi_create_mcfg(struct acpi_mcfg *mcfg) static void enter_acpi_mode(int pm1_cnt) { + u16 val = inw(pm1_cnt); + /* * PM1_CNT register bit0 selects the power management event to be * either an SCI or SMI interrupt. When this bit is set, then power @@ -320,7 +322,7 @@ static void enter_acpi_mode(int pm1_cnt) * system, and expose ourselves to OSPM as working under ACPI mode * already, turn this bit on. */ - outw(PM1_CNT_SCI_EN, pm1_cnt); + outw(val | PM1_CNT_SCI_EN, pm1_cnt); } /* -- 2.39.5