diff options
Diffstat (limited to 'drivers/idle/intel_idle.c')
| -rw-r--r-- | drivers/idle/intel_idle.c | 17 |
1 files changed, 10 insertions, 7 deletions
diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c index 9a810e4a7946..01bace49a962 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) */ /* @@ -1212,14 +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; } @@ -1236,7 +1239,7 @@ static void __init intel_idle_init_cstates_acpi(struct cpuidle_driver *drv) struct acpi_processor_cx *cx; struct cpuidle_state *state; - if (intel_idle_max_cstate_reached(cstate)) + if (intel_idle_max_cstate_reached(cstate - 1)) break; cx = &acpi_state_table.states[cstate]; |