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acpi_cpu: do not apply P_LVLx_LAT rules to latencies returned by _CST

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ACPI specification sates that if P_LVL2_LAT > 100, then a system doesn't
support C2; if P_LVL3_LAT > 1000, then C3 is not supported.
But there are no such rules for Cx state data returned by _CST.  If a
state is not supported it should not be included into the return
package.  In other words, any latency value returned by _CST is valid,
it's up to the OS and/or user to decide whether to use it.

Submitted by:	nork
Suggested by:	mav
MFC after:	1 week
This commit is contained in:
Andriy Gapon 2010-09-13 09:51:24 +00:00
parent fa1efe5efd
commit 09c22c66e1
1 changed files with 1 additions and 9 deletions
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10
sys/dev/acpica/acpi_cpu.c
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@ -690,19 +690,11 @@ acpi_cpu_cx_cst(struct acpi_cpu_softc *sc)
sc->cpu_cx_count++;
continue;
case ACPI_STATE_C2:
if (cx_ptr->trans_lat > 100) {
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"acpi_cpu%d: C2[%d] not available.\n",
device_get_unit(sc->cpu_dev), i));
continue;
}
sc->cpu_non_c3 = i;
break;
case ACPI_STATE_C3:
default:
if (cx_ptr->trans_lat > 1000 ||
(cpu_quirks & CPU_QUIRK_NO_C3) != 0) {
if ((cpu_quirks & CPU_QUIRK_NO_C3) != 0) {
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"acpi_cpu%d: C3[%d] not available.\n",
device_get_unit(sc->cpu_dev), i));