From: Rafael J. Wysocki <rjw@xxxxxxx>
Subject: ACPI hibernate: Introduce new kernel parameter acpi_sleep=s4_nonvs
On some machines it may be necessary to disable the saving/restoring
of the ACPI NVS memory region during hibernation/resume. For this
purpose, introduce new ACPI kernel command line option
acpi_sleep=s4_nonvs.
Based on a patch by Zhang Rui.
Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>
Acked-by: Nigel Cunningham <nigel@xxxxxxxxxxxx>
Acked-by: Pavel Machek <pavel@xxxxxxx>
Cc: Zhang Rui <rui.zhang@xxxxxxxxx>
---
Documentation/kernel-parameters.txt | 5 ++++-
arch/x86/kernel/acpi/sleep.c | 2 ++
drivers/acpi/sleep/main.c | 19 +++++++++++++++++--
include/linux/acpi.h | 1 +
4 files changed, 24 insertions(+), 3 deletions(-)
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 343e0f0..9567123 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -149,7 +149,8 @@ and is between 256 and 4096 characters. It is defined in the file
default: 0
acpi_sleep= [HW,ACPI] Sleep options
- Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig, old_ordering }
+ Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig,
+ old_ordering, s4_nonvs }
See Documentation/power/video.txt for s3_bios and s3_mode.
s3_beep is for debugging; it makes the PC's speaker beep
as soon as the kernel's real-mode entry point is called.
@@ -159,6 +160,8 @@ and is between 256 and 4096 characters. It is defined in the file
control method, wrt putting devices into low power
states, to be enforced (the ACPI 2.0 ordering of _PTS is
used by default).
+ s4_nonvs prevents the kernel from saving/restoring the
+ ACPI NVS memory during hibernation.
acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
Format: { level | edge | high | low }
diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c
index f8a12a8..1d3f36c 100644
--- a/arch/x86/kernel/acpi/sleep.c
+++ b/arch/x86/kernel/acpi/sleep.c
@@ -161,6 +161,8 @@ static int __init acpi_sleep_setup(char *str)
#endif
if (strncmp(str, "old_ordering", 12) == 0)
acpi_old_suspend_ordering();
+ if (strncmp(str, "s4_nonvs", 8) == 0)
+ acpi_s4_no_nvs();
str = strchr(str, ',');
if (str != NULL)
str += strspn(str, ", \t");
diff --git a/drivers/acpi/sleep/main.c b/drivers/acpi/sleep/main.c
index f861b73..63bff78 100644
--- a/drivers/acpi/sleep/main.c
+++ b/drivers/acpi/sleep/main.c
@@ -90,6 +90,20 @@ void __init acpi_old_suspend_ordering(void)
old_suspend_ordering = true;
}
+/*
+ * The ACPI specification wants us to save NVS memory regions during hibernation
+ * and to restore them during the subsequent resume. However, it is not certain
+ * if this mechanism is going to work on all machines, so we allow the user to
+ * disable this mechanism using the 'acpi_sleep=s4_nonvs' kernel command line
+ * option.
+ */
+static bool s4_no_nvs;
+
+void __init acpi_s4_no_nvs(void)
+{
+ s4_no_nvs = true;
+}
+
/**
* acpi_pm_disable_gpes - Disable the GPEs.
*/
@@ -358,7 +372,7 @@ static int acpi_hibernation_begin(void)
{
int error;
- error = hibernate_nvs_alloc();
+ error = s4_no_nvs ? 0 : hibernate_nvs_alloc();
if (!error) {
acpi_target_sleep_state = ACPI_STATE_S4;
acpi_sleep_tts_switch(acpi_target_sleep_state);
@@ -456,7 +470,8 @@ static int acpi_hibernation_begin_old(void)
error = acpi_sleep_prepare(ACPI_STATE_S4);
if (!error) {
- error = hibernate_nvs_alloc();
+ if (!s4_no_nvs)
+ error = hibernate_nvs_alloc();
if (!error)
acpi_target_sleep_state = ACPI_STATE_S4;
}
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index fd6a452..4008f61 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -230,6 +230,7 @@ int acpi_check_mem_region(resource_size_t start, resource_size_t n,
#ifdef CONFIG_PM_SLEEP
void __init acpi_no_s4_hw_signature(void);
void __init acpi_old_suspend_ordering(void);
+void __init acpi_s4_no_nvs(void);
#endif /* CONFIG_PM_SLEEP */
#else /* CONFIG_ACPI */
--
1.5.6
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