Comment 4 for bug 1257353

On 05/12/13 10:07, Alex Hung wrote:
> There is no acpidump for detailed analysis, but let me provide some
> basic information first.
>
>>From the description there are three types of errors:
>
> (1) SystemIO conflicts (Low failures)
> (2). No handler for IPMI (one High failures)
> (3) AE_NOT_FOUND errors (other High failures and Critical failures)
>
> (1) is not really an issue. It is kernel complains there are overlaps on
> what BIOS and kernel can controls and there can potentially race
> conditions on the IO resources - however it is how Intel designs their
> chipset.
>
> (2) means Linux kernel does not include an ACPI IPMI driver. This is not
> a program if IPMI is not used or IPMI is controlled by other methods,
> i.e. another IPMI driver.
>
> (3) means there are errors in BIOS AML. This may or may not be
> important, depending on whether such functions are used.
>
> _GAI and _PMM are control method of "Power Meters" (ACPI Section 10.4) as below:
> _GAI: Gets the averaging interval used by the power meter.
> _PMM: Returns the power consumption measured by the Power Meter.
>
> If any tool is using them, it will fail; otherwise, no misbehaviours
> will been seen.

I believe these aren't really used much nowadays, but I guess we should
check this someday to see if this assumption is correct or not.

>
> _OSC, on the other hand, is more generic and may have more impacts.
>
> ACPI 6.2.10 _OSC (Operating System Capabilities)
>
> This optional object is a control method that is used by OSPM to
> communicate to the platform the feature support or capabilities provided
> by a device’s driver. This object is a child object of a device and may
> also exist in the \_SB scope, where it can be used to convey platform
> wide OSPM capabilities. When supported, _OSC is invoked by OSPM
> immediately after placing the device in the D0 power state. Device
> specific objects are evaluated after _OSC invocation. This allows the
> values returned from other objects to be predicated on the OSPM feature
> support / capability information conveyed by _OSC. OSPM may evaluate
> _OSC multiple times to indicate changes in OSPM capability to the device
> but this may be precluded by specific device requirements.
>
> In summary, failing to evaluate _OSC may cause some features to be
> disabled. For instance, some advanced PCIe features such as ASPM or PCIE
> hotplug will be disabled.

Is the fwts _OSC failure advice sufficient, or should we make it more
verbose to explain what's going on here?
>
> While it may not cause obvious failure if no advanced features are
> needed for this platform, it is still advised to fix AE_NOT_FOUND errors
> if possible. acpidump may help what is missing to cause AE_NOT_FOUND
> errors.
>
>
>
>
> ** Changed in: fwts
> Status: In Progress => Incomplete
>