Merge git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux

1 files changed, 35 insertions, 0 deletions

diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c
index 9cb975200cac..fbfcce3b5227 100644
--- a/drivers/acpi/sleep.c
+++ b/drivers/acpi/sleep.c
@@ -19,6 +19,7 @@
 #include <linux/reboot.h>
 #include <linux/acpi.h>
 #include <linux/module.h>
+#include <linux/syscore_ops.h>
 #include <asm/io.h>
 #include <trace/events/power.h>
 
@@ -677,6 +678,39 @@ static void acpi_sleep_suspend_setup(void)
 static inline void acpi_sleep_suspend_setup(void) {}
 #endif /* !CONFIG_SUSPEND */
 
+#ifdef CONFIG_PM_SLEEP
+static u32 saved_bm_rld;
+
+static int  acpi_save_bm_rld(void)
+{
+	acpi_read_bit_register(ACPI_BITREG_BUS_MASTER_RLD, &saved_bm_rld);
+	return 0;
+}
+
+static void  acpi_restore_bm_rld(void)
+{
+	u32 resumed_bm_rld = 0;
+
+	acpi_read_bit_register(ACPI_BITREG_BUS_MASTER_RLD, &resumed_bm_rld);
+	if (resumed_bm_rld == saved_bm_rld)
+		return;
+
+	acpi_write_bit_register(ACPI_BITREG_BUS_MASTER_RLD, saved_bm_rld);
+}
+
+static struct syscore_ops acpi_sleep_syscore_ops = {
+	.suspend = acpi_save_bm_rld,
+	.resume = acpi_restore_bm_rld,
+};
+
+void acpi_sleep_syscore_init(void)
+{
+	register_syscore_ops(&acpi_sleep_syscore_ops);
+}
+#else
+static inline void acpi_sleep_syscore_init(void) {}
+#endif /* CONFIG_PM_SLEEP */
+
 #ifdef CONFIG_HIBERNATION
 static unsigned long s4_hardware_signature;
 static struct acpi_table_facs *facs;
@@ -839,6 +873,7 @@ int __init acpi_sleep_init(void)
 
 	sleep_states[ACPI_STATE_S0] = 1;
 
+	acpi_sleep_syscore_init();
 	acpi_sleep_suspend_setup();
 	acpi_sleep_hibernate_setup();