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ACPICA: AcpiGetDevices: Eliminate unnecessary _STA calls

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In the case where a specific _HID is requested, do not run _STA
until a _HID match is found. This eliminates potentially dozens
of _STA calls during a search for a particular device/HID.

Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
This commit is contained in:
Lin Ming 2010-01-21 09:15:20 +08:00 committed by Len Brown
parent a8357b0c95
commit 5f8902acf8
1 changed files with 33 additions and 19 deletions
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52
drivers/acpi/acpica/nsxfeval.c
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@ -562,25 +562,20 @@ acpi_ns_get_device_callback(acpi_handle obj_handle,
return (AE_BAD_PARAMETER);
}
/* Run _STA to determine if device is present */
status = acpi_ut_execute_STA(node, &flags);
if (ACPI_FAILURE(status)) {
return (AE_CTRL_DEPTH);
}
if (!(flags & ACPI_STA_DEVICE_PRESENT) &&
!(flags & ACPI_STA_DEVICE_FUNCTIONING)) {
/*
* Don't examine the children of the device only when the
* device is neither present nor functional. See ACPI spec,
* description of _STA for more information.
*/
return (AE_CTRL_DEPTH);
}
/* Filter based on device HID & CID */
/*
* First, filter based on the device HID and CID.
*
* 01/2010: For this case where a specific HID is requested, we don't
* want to run _STA until we have an actual HID match. Thus, we will
* not unnecessarily execute _STA on devices for which the caller
* doesn't care about. Previously, _STA was executed unconditionally
* on all devices found here.
*
* A side-effect of this change is that now we will continue to search
* for a matching HID even under device trees where the parent device
* would have returned a _STA that indicates it is not present or
* not functioning (thus aborting the search on that branch).
*/
if (info->hid != NULL) {
status = acpi_ut_execute_HID(node, &hid);
if (status == AE_NOT_FOUND) {
@ -620,6 +615,25 @@ acpi_ns_get_device_callback(acpi_handle obj_handle,
}
}
/* Run _STA to determine if device is present */
status = acpi_ut_execute_STA(node, &flags);
if (ACPI_FAILURE(status)) {
return (AE_CTRL_DEPTH);
}
if (!(flags & ACPI_STA_DEVICE_PRESENT) &&
!(flags & ACPI_STA_DEVICE_FUNCTIONING)) {
/*
* Don't examine the children of the device only when the
* device is neither present nor functional. See ACPI spec,
* description of _STA for more information.
*/
return (AE_CTRL_DEPTH);
}
/* We have a valid device, invoke the user function */
status = info->user_function(obj_handle, nesting_level, info->context,
return_value);
return (status);