intel_idle: Use ACPI _CST on server systems

In many cases, especially on server systems, it is desirable to avoid
enabling C-states that have been disabled in the platform firmware
(BIOS) setup, except for C1E.

As a rule, the C-states disabled this way are not listed by ACPI
_CST, so if that is used by intel_idle along with the specific
table of C-states that it has for the given processor, the C-states
disabled through the platform firmware will not be enabled by default
by intel_idle.

Accordingly, set the use_acpi flag (introduced previously) in all
server processor profiles defined in intel_idle (so as to make it use
ACPI _CST to decide which C-states to enable by default) and set
the CPUIDLE_FLAG_ALWAYS_ENABLE flag (also introduced previously)
for C1E in all C-states tables in intel_idle that contain C1 too
(so that C1E is enabled regardless of whether or not it is listed
by ACPI _CST).
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/idle/intel_idle.c

@@ -131,7 +131,7 @@ static struct cpuidle_state nehalem_cstates[] = {
 	{
 		.name = "C1E",
 		.desc = "MWAIT 0x01",
-		.flags = MWAIT2flg(0x01),
+		.flags = MWAIT2flg(0x01) | CPUIDLE_FLAG_ALWAYS_ENABLE,
 		.exit_latency = 10,
 		.target_residency = 20,
 		.enter = &intel_idle,
@@ -168,7 +168,7 @@ static struct cpuidle_state snb_cstates[] = {
 	{
 		.name = "C1E",
 		.desc = "MWAIT 0x01",
-		.flags = MWAIT2flg(0x01),
+		.flags = MWAIT2flg(0x01) | CPUIDLE_FLAG_ALWAYS_ENABLE,
 		.exit_latency = 10,
 		.target_residency = 20,
 		.enter = &intel_idle,
@@ -303,7 +303,7 @@ static struct cpuidle_state ivb_cstates[] = {
 	{
 		.name = "C1E",
 		.desc = "MWAIT 0x01",
-		.flags = MWAIT2flg(0x01),
+		.flags = MWAIT2flg(0x01) | CPUIDLE_FLAG_ALWAYS_ENABLE,
 		.exit_latency = 10,
 		.target_residency = 20,
 		.enter = &intel_idle,
@@ -348,7 +348,7 @@ static struct cpuidle_state ivt_cstates[] = {
 	{
 		.name = "C1E",
 		.desc = "MWAIT 0x01",
-		.flags = MWAIT2flg(0x01),
+		.flags = MWAIT2flg(0x01) | CPUIDLE_FLAG_ALWAYS_ENABLE,
 		.exit_latency = 10,
 		.target_residency = 80,
 		.enter = &intel_idle,
@@ -385,7 +385,7 @@ static struct cpuidle_state ivt_cstates_4s[] = {
 	{
 		.name = "C1E",
 		.desc = "MWAIT 0x01",
-		.flags = MWAIT2flg(0x01),
+		.flags = MWAIT2flg(0x01) | CPUIDLE_FLAG_ALWAYS_ENABLE,
 		.exit_latency = 10,
 		.target_residency = 250,
 		.enter = &intel_idle,
@@ -422,7 +422,7 @@ static struct cpuidle_state ivt_cstates_8s[] = {
 	{
 		.name = "C1E",
 		.desc = "MWAIT 0x01",
-		.flags = MWAIT2flg(0x01),
+		.flags = MWAIT2flg(0x01) | CPUIDLE_FLAG_ALWAYS_ENABLE,
 		.exit_latency = 10,
 		.target_residency = 500,
 		.enter = &intel_idle,
@@ -459,7 +459,7 @@ static struct cpuidle_state hsw_cstates[] = {
 	{
 		.name = "C1E",
 		.desc = "MWAIT 0x01",
-		.flags = MWAIT2flg(0x01),
+		.flags = MWAIT2flg(0x01) | CPUIDLE_FLAG_ALWAYS_ENABLE,
 		.exit_latency = 10,
 		.target_residency = 20,
 		.enter = &intel_idle,
@@ -527,7 +527,7 @@ static struct cpuidle_state bdw_cstates[] = {
 	{
 		.name = "C1E",
 		.desc = "MWAIT 0x01",
-		.flags = MWAIT2flg(0x01),
+		.flags = MWAIT2flg(0x01) | CPUIDLE_FLAG_ALWAYS_ENABLE,
 		.exit_latency = 10,
 		.target_residency = 20,
 		.enter = &intel_idle,
@@ -596,7 +596,7 @@ static struct cpuidle_state skl_cstates[] = {
 	{
 		.name = "C1E",
 		.desc = "MWAIT 0x01",
-		.flags = MWAIT2flg(0x01),
+		.flags = MWAIT2flg(0x01) | CPUIDLE_FLAG_ALWAYS_ENABLE,
 		.exit_latency = 10,
 		.target_residency = 20,
 		.enter = &intel_idle,
@@ -665,7 +665,7 @@ static struct cpuidle_state skx_cstates[] = {
 	{
 		.name = "C1E",
 		.desc = "MWAIT 0x01",
-		.flags = MWAIT2flg(0x01),
+		.flags = MWAIT2flg(0x01) | CPUIDLE_FLAG_ALWAYS_ENABLE,
 		.exit_latency = 10,
 		.target_residency = 20,
 		.enter = &intel_idle,
@@ -815,7 +815,7 @@ static struct cpuidle_state bxt_cstates[] = {
 	{
 		.name = "C1E",
 		.desc = "MWAIT 0x01",
-		.flags = MWAIT2flg(0x01),
+		.flags = MWAIT2flg(0x01) | CPUIDLE_FLAG_ALWAYS_ENABLE,
 		.exit_latency = 10,
 		.target_residency = 20,
 		.enter = &intel_idle,
@@ -876,7 +876,7 @@ static struct cpuidle_state dnv_cstates[] = {
 	{
 		.name = "C1E",
 		.desc = "MWAIT 0x01",
-		.flags = MWAIT2flg(0x01),
+		.flags = MWAIT2flg(0x01) | CPUIDLE_FLAG_ALWAYS_ENABLE,
 		.exit_latency = 10,
 		.target_residency = 20,
 		.enter = &intel_idle,
@@ -998,6 +998,13 @@ static const struct idle_cpu idle_cpu_nehalem = {
 	.disable_promotion_to_c1e = true,
 };
 
+static const struct idle_cpu idle_cpu_nhx = {
+	.state_table = nehalem_cstates,
+	.auto_demotion_disable_flags = NHM_C1_AUTO_DEMOTE | NHM_C3_AUTO_DEMOTE,
+	.disable_promotion_to_c1e = true,
+	.use_acpi = true,
+};
+
 static const struct idle_cpu idle_cpu_atom = {
 	.state_table = atom_cstates,
 };
@@ -1016,6 +1023,12 @@ static const struct idle_cpu idle_cpu_snb = {
 	.disable_promotion_to_c1e = true,
 };
 
+static const struct idle_cpu idle_cpu_snx = {
+	.state_table = snb_cstates,
+	.disable_promotion_to_c1e = true,
+	.use_acpi = true,
+};
+
 static const struct idle_cpu idle_cpu_byt = {
 	.state_table = byt_cstates,
 	.disable_promotion_to_c1e = true,
@@ -1036,6 +1049,7 @@ static const struct idle_cpu idle_cpu_ivb = {
 static const struct idle_cpu idle_cpu_ivt = {
 	.state_table = ivt_cstates,
 	.disable_promotion_to_c1e = true,
+	.use_acpi = true,
 };
 
 static const struct idle_cpu idle_cpu_hsw = {
@@ -1043,11 +1057,23 @@ static const struct idle_cpu idle_cpu_hsw = {
 	.disable_promotion_to_c1e = true,
 };
 
+static const struct idle_cpu idle_cpu_hsx = {
+	.state_table = hsw_cstates,
+	.disable_promotion_to_c1e = true,
+	.use_acpi = true,
+};
+
 static const struct idle_cpu idle_cpu_bdw = {
 	.state_table = bdw_cstates,
 	.disable_promotion_to_c1e = true,
 };
 
+static const struct idle_cpu idle_cpu_bdx = {
+	.state_table = bdw_cstates,
+	.disable_promotion_to_c1e = true,
+	.use_acpi = true,
+};
+
 static const struct idle_cpu idle_cpu_skl = {
 	.state_table = skl_cstates,
 	.disable_promotion_to_c1e = true,
@@ -1056,15 +1082,18 @@ static const struct idle_cpu idle_cpu_skl = {
 static const struct idle_cpu idle_cpu_skx = {
 	.state_table = skx_cstates,
 	.disable_promotion_to_c1e = true,
+	.use_acpi = true,
 };
 
 static const struct idle_cpu idle_cpu_avn = {
 	.state_table = avn_cstates,
 	.disable_promotion_to_c1e = true,
+	.use_acpi = true,
 };
 
 static const struct idle_cpu idle_cpu_knl = {
 	.state_table = knl_cstates,
+	.use_acpi = true,
 };
 
 static const struct idle_cpu idle_cpu_bxt = {
@@ -1075,20 +1104,21 @@ static const struct idle_cpu idle_cpu_bxt = {
 static const struct idle_cpu idle_cpu_dnv = {
 	.state_table = dnv_cstates,
 	.disable_promotion_to_c1e = true,
+	.use_acpi = true,
 };
 
 static const struct x86_cpu_id intel_idle_ids[] __initconst = {
-	INTEL_CPU_FAM6(NEHALEM_EP,		idle_cpu_nehalem),
+	INTEL_CPU_FAM6(NEHALEM_EP,		idle_cpu_nhx),
 	INTEL_CPU_FAM6(NEHALEM,			idle_cpu_nehalem),
 	INTEL_CPU_FAM6(NEHALEM_G,		idle_cpu_nehalem),
 	INTEL_CPU_FAM6(WESTMERE,		idle_cpu_nehalem),
-	INTEL_CPU_FAM6(WESTMERE_EP,		idle_cpu_nehalem),
-	INTEL_CPU_FAM6(NEHALEM_EX,		idle_cpu_nehalem),
+	INTEL_CPU_FAM6(WESTMERE_EP,		idle_cpu_nhx),
+	INTEL_CPU_FAM6(NEHALEM_EX,		idle_cpu_nhx),
 	INTEL_CPU_FAM6(ATOM_BONNELL,		idle_cpu_atom),
 	INTEL_CPU_FAM6(ATOM_BONNELL_MID,	idle_cpu_lincroft),
-	INTEL_CPU_FAM6(WESTMERE_EX,		idle_cpu_nehalem),
+	INTEL_CPU_FAM6(WESTMERE_EX,		idle_cpu_nhx),
 	INTEL_CPU_FAM6(SANDYBRIDGE,		idle_cpu_snb),
-	INTEL_CPU_FAM6(SANDYBRIDGE_X,		idle_cpu_snb),
+	INTEL_CPU_FAM6(SANDYBRIDGE_X,		idle_cpu_snx),
 	INTEL_CPU_FAM6(ATOM_SALTWELL,		idle_cpu_atom),
 	INTEL_CPU_FAM6(ATOM_SILVERMONT,		idle_cpu_byt),
 	INTEL_CPU_FAM6(ATOM_SILVERMONT_MID,	idle_cpu_tangier),
@@ -1096,14 +1126,14 @@ static const struct x86_cpu_id intel_idle_ids[] __initconst = {
 	INTEL_CPU_FAM6(IVYBRIDGE,		idle_cpu_ivb),
 	INTEL_CPU_FAM6(IVYBRIDGE_X,		idle_cpu_ivt),
 	INTEL_CPU_FAM6(HASWELL,			idle_cpu_hsw),
-	INTEL_CPU_FAM6(HASWELL_X,		idle_cpu_hsw),
+	INTEL_CPU_FAM6(HASWELL_X,		idle_cpu_hsx),
 	INTEL_CPU_FAM6(HASWELL_L,		idle_cpu_hsw),
 	INTEL_CPU_FAM6(HASWELL_G,		idle_cpu_hsw),
 	INTEL_CPU_FAM6(ATOM_SILVERMONT_D,	idle_cpu_avn),
 	INTEL_CPU_FAM6(BROADWELL,		idle_cpu_bdw),
 	INTEL_CPU_FAM6(BROADWELL_G,		idle_cpu_bdw),
-	INTEL_CPU_FAM6(BROADWELL_X,		idle_cpu_bdw),
-	INTEL_CPU_FAM6(BROADWELL_D,		idle_cpu_bdw),
+	INTEL_CPU_FAM6(BROADWELL_X,		idle_cpu_bdx),
+	INTEL_CPU_FAM6(BROADWELL_D,		idle_cpu_bdx),
 	INTEL_CPU_FAM6(SKYLAKE_L,		idle_cpu_skl),
 	INTEL_CPU_FAM6(SKYLAKE,			idle_cpu_skl),
 	INTEL_CPU_FAM6(KABYLAKE_L,		idle_cpu_skl),