diff options
Diffstat (limited to 'drivers/idle/intel_idle.c')
| -rw-r--r-- | drivers/idle/intel_idle.c | 31 |
1 files changed, 9 insertions, 22 deletions
diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c index 8e0fb1a5bdbd..56f5b8077cba 100644 --- a/drivers/idle/intel_idle.c +++ b/drivers/idle/intel_idle.c @@ -8,7 +8,7 @@ */ /* - * intel_idle is a cpuidle driver that loads on specific Intel processors + * intel_idle is a cpuidle driver that loads on all Intel CPUs with MWAIT * in lieu of the legacy ACPI processor_idle driver. The intent is to * make Linux more efficient on these processors, as intel_idle knows * more than ACPI, as well as make Linux more immune to ACPI BIOS bugs. @@ -20,7 +20,11 @@ * All CPUs have same idle states as boot CPU * * Chipset BM_STS (bus master status) bit is a NOP - * for preventing entry into deep C-stats + * for preventing entry into deep C-states + * + * CPU will flush caches as needed when entering a C-state via MWAIT + * (in contrast to entering ACPI C3, in which case the WBINVD + * instruction needs to be executed to flush the caches) */ /* @@ -90,14 +94,6 @@ static unsigned int mwait_substates __initdata; #define CPUIDLE_FLAG_ALWAYS_ENABLE BIT(15) /* - * Set this flag for states where the HW flushes the TLB for us - * and so we don't need cross-calls to keep it consistent. - * If this flag is set, SW flushes the TLB, so even if the - * HW doesn't do the flushing, this flag is safe to use. - */ -#define CPUIDLE_FLAG_TLB_FLUSHED BIT(16) - -/* * MWAIT takes an 8-bit "hint" in EAX "suggesting" * the C-state (top nibble) and sub-state (bottom nibble) * 0x00 means "MWAIT(C1)", 0x10 means "MWAIT(C2)" etc. @@ -131,14 +127,6 @@ static __cpuidle int intel_idle(struct cpuidle_device *dev, unsigned long eax = flg2MWAIT(state->flags); unsigned long ecx = 1; /* break on interrupt flag */ bool tick; - int cpu = smp_processor_id(); - - /* - * leave_mm() to avoid costly and often unnecessary wakeups - * for flushing the user TLB's associated with the active mm. - */ - if (state->flags & CPUIDLE_FLAG_TLB_FLUSHED) - leave_mm(cpu); if (!static_cpu_has(X86_FEATURE_ARAT)) { /* @@ -1228,14 +1216,13 @@ static bool __init intel_idle_acpi_cst_extract(void) if (!intel_idle_cst_usable()) continue; - if (!acpi_processor_claim_cst_control()) { - acpi_state_table.count = 0; - return false; - } + if (!acpi_processor_claim_cst_control()) + break; return true; } + acpi_state_table.count = 0; pr_debug("ACPI _CST not found or not usable\n"); return false; } |