ACPI / Sleep: Allow the NVS saving to be skipped during suspend to RAM

Commit 2a6b69765ad794389f2fc3e14a0afa1a995221c2
(ACPI: Store NVS state even when entering suspend to RAM) caused the
ACPI suspend code save the NVS area during suspend and restore it
during resume unconditionally, although it is known that some systems
need to use acpi_sleep=s4_nonvs for hibernation to work.  To allow
the affected systems to avoid saving and restoring the NVS area
during suspend to RAM and resume, introduce kernel command line
option acpi_sleep=nonvs and make acpi_sleep=s4_nonvs work as its
alias temporarily (add acpi_sleep=s4_nonvs to the feature removal
file).

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=16396 .

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Reported-and-tested-by: tomas m <tmezzadra@gmail.com>
Signed-off-by: Len Brown <len.brown@intel.com>

diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt
index c268783bc4e7c18c2e4db792c3fba83d6bc44c71..1571c0c83dba0b0876ea52e4ff85ff69a56dab87 100644 (file)
--- a/Documentation/feature-removal-schedule.txt
+++ b/Documentation/feature-removal-schedule.txt
@@ -647,3 +647,10 @@ Who:       Stefan Richter <stefanr@s5r6.in-berlin.de>
 
 ----------------------------
 
+What:  The acpi_sleep=s4_nonvs command line option
+When:  2.6.37
+Files: arch/x86/kernel/acpi/sleep.c
+Why:   superseded by acpi_sleep=nonvs
+Who:   Rafael J. Wysocki <rjw@sisk.pl>
+
+----------------------------

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 4ddb58df081e360311e22cafe40273d3176de46d..2b2407d9a6d025a8451605b104a35daa7da59b47 100644 (file)
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -254,8 +254,8 @@ and is between 256 and 4096 characters. It is defined in the file
                        control method, with respect to 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.
+                       nonvs prevents the kernel from saving/restoring the
+                       ACPI NVS memory during suspend/hibernation and resume.
                        sci_force_enable causes the kernel to set SCI_EN directly
                        on resume from S1/S3 (which is against the ACPI spec,
                        but some broken systems don't work without it).

diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c
index 82e508677b91116ec8428e434ae164a8390084bf..fcc3c61fdecc0a8e73859868f5f863c9fdb315e3 100644 (file)
--- a/arch/x86/kernel/acpi/sleep.c
+++ b/arch/x86/kernel/acpi/sleep.c
@@ -157,9 +157,14 @@ static int __init acpi_sleep_setup(char *str)
 #ifdef CONFIG_HIBERNATION
                if (strncmp(str, "s4_nohwsig", 10) == 0)
                        acpi_no_s4_hw_signature();
-               if (strncmp(str, "s4_nonvs", 8) == 0)
-                       acpi_s4_no_nvs();
+               if (strncmp(str, "s4_nonvs", 8) == 0) {
+                       pr_warning("ACPI: acpi_sleep=s4_nonvs is deprecated, "
+                                       "please use acpi_sleep=nonvs instead");
+                       acpi_nvs_nosave();
+               }
 #endif
+               if (strncmp(str, "nonvs", 5) == 0)
+                       acpi_nvs_nosave();
                if (strncmp(str, "old_ordering", 12) == 0)
                        acpi_old_suspend_ordering();
                str = strchr(str, ',');

diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c
index 5b7c52e4a00f09001becab5df101e7e5fa4dabc8..2862c781b37266aecee8052dac047aa2bcb31ef2 100644 (file)
--- a/drivers/acpi/sleep.c
+++ b/drivers/acpi/sleep.c
@@ -81,6 +81,20 @@ static int acpi_sleep_prepare(u32 acpi_state)
 #ifdef CONFIG_ACPI_SLEEP
 static u32 acpi_target_sleep_state = ACPI_STATE_S0;
 
+/*
+ * The ACPI specification wants us to save NVS memory regions during hibernation
+ * and to restore them during the subsequent resume.  Windows does that also for
+ * suspend to RAM.  However, it is known that this mechanism does not work on
+ * all machines, so we allow the user to disable it with the help of the
+ * 'acpi_sleep=nonvs' kernel command line option.
+ */
+static bool nvs_nosave;
+
+void __init acpi_nvs_nosave(void)
+{
+       nvs_nosave = true;
+}
+
 /*
  * ACPI 1.0 wants us to execute _PTS before suspending devices, so we allow the
  * user to request that behavior by using the 'acpi_old_suspend_ordering'
@@ -197,8 +211,7 @@ static int acpi_suspend_begin(suspend_state_t pm_state)
        u32 acpi_state = acpi_suspend_states[pm_state];
        int error = 0;
 
-       error = suspend_nvs_alloc();
-
+       error = nvs_nosave ? 0 : suspend_nvs_alloc();
        if (error)
                return error;
 
@@ -388,20 +401,6 @@ static struct dmi_system_id __initdata acpisleep_dmi_table[] = {
 #endif /* CONFIG_SUSPEND */
 
 #ifdef CONFIG_HIBERNATION
-/*
- * 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;
-}
-
 static unsigned long s4_hardware_signature;
 static struct acpi_table_facs *facs;
 static bool nosigcheck;
@@ -415,7 +414,7 @@ static int acpi_hibernation_begin(void)
 {
        int error;
 
-       error = s4_no_nvs ? 0 : suspend_nvs_alloc();
+       error = nvs_nosave ? 0 : suspend_nvs_alloc();
        if (!error) {
                acpi_target_sleep_state = ACPI_STATE_S4;
                acpi_sleep_tts_switch(acpi_target_sleep_state);
@@ -510,7 +509,7 @@ static int acpi_hibernation_begin_old(void)
        error = acpi_sleep_prepare(ACPI_STATE_S4);
 
        if (!error) {
-               if (!s4_no_nvs)
+               if (!nvs_nosave)
                        error = suspend_nvs_alloc();
                if (!error)
                        acpi_target_sleep_state = ACPI_STATE_S4;

diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 224a38c960d4c01830eb96987325d88aee33a2bf..ccf94dc5acdf0ba8cc4f836968f103f542ff43b6 100644 (file)
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -253,7 +253,7 @@ int acpi_resources_are_enforced(void);
 #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);
+void __init acpi_nvs_nosave(void);
 #endif /* CONFIG_PM_SLEEP */
 
 struct acpi_osc_context {