#include <linux/dmi.h>
#include <linux/moduleparam.h>
#include <linux/sched.h> /* need_resched() */
+#include <linux/latency.h>
#include <asm/io.h>
#include <asm/uaccess.h>
*/
if (cx->promotion.state &&
((cx->promotion.state - pr->power.states) <= max_cstate)) {
- if (sleep_ticks > cx->promotion.threshold.ticks) {
+ if (sleep_ticks > cx->promotion.threshold.ticks &&
+ cx->promotion.state->latency <= system_latency_constraint()) {
cx->promotion.count++;
cx->demotion.count = 0;
if (cx->promotion.count >=
end:
/*
* Demote if current state exceeds max_cstate
+ * or if the latency of the current state is unacceptable
*/
- if ((pr->power.state - pr->power.states) > max_cstate) {
+ if ((pr->power.state - pr->power.states) > max_cstate ||
+ pr->power.state->latency > system_latency_constraint()) {
if (cx->demotion.state)
next_state = cx->demotion.state;
}
return -ENODEV;
}
- cst = (union acpi_object *)buffer.pointer;
+ cst = buffer.pointer;
/* There must be at least 2 elements */
if (!cst || (cst->type != ACPI_TYPE_PACKAGE) || cst->package.count < 2) {
memset(&cx, 0, sizeof(cx));
- element = (union acpi_object *)&(cst->package.elements[i]);
+ element = &(cst->package.elements[i]);
if (element->type != ACPI_TYPE_PACKAGE)
continue;
if (element->package.count != 4)
continue;
- obj = (union acpi_object *)&(element->package.elements[0]);
+ obj = &(element->package.elements[0]);
if (obj->type != ACPI_TYPE_BUFFER)
continue;
0 : reg->address;
/* There should be an easy way to extract an integer... */
- obj = (union acpi_object *)&(element->package.elements[1]);
+ obj = &(element->package.elements[1]);
if (obj->type != ACPI_TYPE_INTEGER)
continue;
if ((cx.type < ACPI_STATE_C2) || (cx.type > ACPI_STATE_C3))
continue;
- obj = (union acpi_object *)&(element->package.elements[2]);
+ obj = &(element->package.elements[2]);
if (obj->type != ACPI_TYPE_INTEGER)
continue;
cx.latency = obj->integer.value;
- obj = (union acpi_object *)&(element->package.elements[3]);
+ obj = &(element->package.elements[3]);
if (obj->type != ACPI_TYPE_INTEGER)
continue;
static int acpi_processor_power_seq_show(struct seq_file *seq, void *offset)
{
- struct acpi_processor *pr = (struct acpi_processor *)seq->private;
+ struct acpi_processor *pr = seq->private;
unsigned int i;
seq_printf(seq, "active state: C%zd\n"
"max_cstate: C%d\n"
- "bus master activity: %08x\n",
+ "bus master activity: %08x\n"
+ "maximum allowed latency: %d usec\n",
pr->power.state ? pr->power.state - pr->power.states : 0,
- max_cstate, (unsigned)pr->power.bm_activity);
+ max_cstate, (unsigned)pr->power.bm_activity,
+ system_latency_constraint());
seq_puts(seq, "states:\n");
.release = single_release,
};
+static void smp_callback(void *v)
+{
+ /* we already woke the CPU up, nothing more to do */
+}
+
+/*
+ * This function gets called when a part of the kernel has a new latency
+ * requirement. This means we need to get all processors out of their C-state,
+ * and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that
+ * wakes them all right up.
+ */
+static int acpi_processor_latency_notify(struct notifier_block *b,
+ unsigned long l, void *v)
+{
+ smp_call_function(smp_callback, NULL, 0, 1);
+ return NOTIFY_OK;
+}
+
+static struct notifier_block acpi_processor_latency_notifier = {
+ .notifier_call = acpi_processor_latency_notify,
+};
+
int acpi_processor_power_init(struct acpi_processor *pr,
struct acpi_device *device)
{
"ACPI: processor limited to max C-state %d\n",
max_cstate);
first_run++;
+ register_latency_notifier(&acpi_processor_latency_notifier);
}
if (!pr)
* copies of pm_idle before proceeding.
*/
cpu_idle_wait();
+ unregister_latency_notifier(&acpi_processor_latency_notifier);
}
return 0;