From ef54d5ad2f58f899be6419fd1090cdeb2439851a Mon Sep 17 00:00:00 2001 From: Zhao Yakui Date: Thu, 15 Nov 2007 16:59:30 +0800 Subject: [PATCH] ACPI: Enforce T-state limit changes immediately When a T-state limit change notification is received, Linux must evaluate _TPC and change its current T-state immediately to comply with the new limit. Previously, Linux would notice the new limit only upon the next throttling change. Signed-off-by: Zhao Yakui Signed-off-by: Li Shaohua Signed-off-by: Len Brown --- drivers/acpi/processor_throttling.c | 50 ++++++++++++++++++++++++++++- 1 file changed, 49 insertions(+), 1 deletion(-) diff --git a/drivers/acpi/processor_throttling.c b/drivers/acpi/processor_throttling.c index 0b8204e7082a..5fa8ac1c0c84 100644 --- a/drivers/acpi/processor_throttling.c +++ b/drivers/acpi/processor_throttling.c @@ -70,7 +70,55 @@ static int acpi_processor_get_platform_limit(struct acpi_processor *pr) int acpi_processor_tstate_has_changed(struct acpi_processor *pr) { - return acpi_processor_get_platform_limit(pr); + int result = 0; + int throttling_limit; + int current_state; + struct acpi_processor_limit *limit; + int target_state; + + result = acpi_processor_get_platform_limit(pr); + if (result) { + /* Throttling Limit is unsupported */ + return result; + } + + throttling_limit = pr->throttling_platform_limit; + if (throttling_limit >= pr->throttling.state_count) { + /* Uncorrect Throttling Limit */ + return -EINVAL; + } + + current_state = pr->throttling.state; + if (current_state > throttling_limit) { + /* + * The current state can meet the requirement of + * _TPC limit. But it is reasonable that OSPM changes + * t-states from high to low for better performance. + * Of course the limit condition of thermal + * and user should be considered. + */ + limit = &pr->limit; + target_state = throttling_limit; + if (limit->thermal.tx > target_state) + target_state = limit->thermal.tx; + if (limit->user.tx > target_state) + target_state = limit->user.tx; + } else if (current_state == throttling_limit) { + /* + * Unnecessary to change the throttling state + */ + return 0; + } else { + /* + * If the current state is lower than the limit of _TPC, it + * will be forced to switch to the throttling state defined + * by throttling_platfor_limit. + * Because the previous state meets with the limit condition + * of thermal and user, it is unnecessary to check it again. + */ + target_state = throttling_limit; + } + return acpi_processor_set_throttling(pr, target_state); } /* -- 2.30.2