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authorLen Brown <len.brown@intel.com>2010-07-22 18:18:28 -0400
committerLen Brown <len.brown@intel.com>2010-07-22 18:18:28 -0400
commit4a973f2495fba8775d1c408b3ee7f2c19b19f13f (patch)
tree302484851e44029a208cce8c79294a82f25561d9
parentbe48b11573952b467676b24de87d637e33339e7d (diff)
parentd3e7e99f2faf9f44ec0a3379f735b41c9173dfa1 (diff)
downloadlinux-4a973f2495fba8775d1c408b3ee7f2c19b19f13f.tar.bz2
Merge branch 'bugzilla-15886' into release
-rw-r--r--arch/x86/kernel/acpi/cstate.c9
-rw-r--r--drivers/acpi/processor_idle.c7
-rw-r--r--include/acpi/processor.h3
3 files changed, 17 insertions, 2 deletions
diff --git a/arch/x86/kernel/acpi/cstate.c b/arch/x86/kernel/acpi/cstate.c
index 2e837f5080fe..fb7a5f052e2b 100644
--- a/arch/x86/kernel/acpi/cstate.c
+++ b/arch/x86/kernel/acpi/cstate.c
@@ -145,6 +145,15 @@ int acpi_processor_ffh_cstate_probe(unsigned int cpu,
percpu_entry->states[cx->index].eax = cx->address;
percpu_entry->states[cx->index].ecx = MWAIT_ECX_INTERRUPT_BREAK;
}
+
+ /*
+ * For _CST FFH on Intel, if GAS.access_size bit 1 is cleared,
+ * then we should skip checking BM_STS for this C-state.
+ * ref: "Intel Processor Vendor-Specific ACPI Interface Specification"
+ */
+ if ((c->x86_vendor == X86_VENDOR_INTEL) && !(reg->access_size & 0x2))
+ cx->bm_sts_skip = 1;
+
return retval;
}
EXPORT_SYMBOL_GPL(acpi_processor_ffh_cstate_probe);
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index b1b385692f46..1d4104855296 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -76,6 +76,8 @@ static unsigned int max_cstate __read_mostly = ACPI_PROCESSOR_MAX_POWER;
module_param(max_cstate, uint, 0000);
static unsigned int nocst __read_mostly;
module_param(nocst, uint, 0000);
+static int bm_check_disable __read_mostly;
+module_param(bm_check_disable, uint, 0000);
static unsigned int latency_factor __read_mostly = 2;
module_param(latency_factor, uint, 0644);
@@ -763,6 +765,9 @@ static int acpi_idle_bm_check(void)
{
u32 bm_status = 0;
+ if (bm_check_disable)
+ return 0;
+
acpi_read_bit_register(ACPI_BITREG_BUS_MASTER_STATUS, &bm_status);
if (bm_status)
acpi_write_bit_register(ACPI_BITREG_BUS_MASTER_STATUS, 1);
@@ -947,7 +952,7 @@ static int acpi_idle_enter_bm(struct cpuidle_device *dev,
if (acpi_idle_suspend)
return(acpi_idle_enter_c1(dev, state));
- if (acpi_idle_bm_check()) {
+ if (!cx->bm_sts_skip && acpi_idle_bm_check()) {
if (dev->safe_state) {
dev->last_state = dev->safe_state;
return dev->safe_state->enter(dev, dev->safe_state);
diff --git a/include/acpi/processor.h b/include/acpi/processor.h
index da565a48240e..a68ca8a11a53 100644
--- a/include/acpi/processor.h
+++ b/include/acpi/processor.h
@@ -48,7 +48,7 @@ struct acpi_power_register {
u8 space_id;
u8 bit_width;
u8 bit_offset;
- u8 reserved;
+ u8 access_size;
u64 address;
} __attribute__ ((packed));
@@ -63,6 +63,7 @@ struct acpi_processor_cx {
u32 power;
u32 usage;
u64 time;
+ u8 bm_sts_skip;
char desc[ACPI_CX_DESC_LEN];
};