Re: [PATCH] ACPI: don't show an error when we're not in charge of PCIe hotplug.

From: Rafael J. Wysocki
Date: Wed Jun 22 2016 - 18:47:59 EST


On Wed, Jun 22, 2016 at 10:53 PM, Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote:
> On Wed, Jun 22, 2016 at 12:43 PM, <Mario_Limonciello@xxxxxxxx> wrote:
>>> -----Original Message-----
>>> From: rjwysocki@xxxxxxxxx [mailto:rjwysocki@xxxxxxxxx] On Behalf Of

[cut]

>> I think changing that would help communicate what's going on here and at
>> least let the user know the result will be that the firmware is still controlling
>> ASPM due to the _OSC failure.

You seem to be assuming that all systems returning "unsupported UUID"
from the PCI host bridge _OSC will always fall into the same category,
but what if they don't? What if at least some of them are really
broken?

>> Something else that I think Andy recommended a while back was at that
>> time try to evaluate NEXP and display its value and an associated message
>> in debug logs when _OSC fails. Would you be amenable to a change like that?
>
> That seems dangerous if NEXP is anything other than a SystemMemory
> variable. I don't know if there's a clean way to check that before
> evaluating it. (i.e. we don't want to hit some other thing called
> NEXP that has side effects.)

Well, that's generic code and NEXP is not generic really, so agreed.

Thanks,
Rafael