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Date:   Wed, 20 Nov 2019 14:09:13 +0200
From:   Mika Westerberg <mika.westerberg@intel.com>
To:     Karol Herbst <kherbst@redhat.com>
Cc:     "Rafael J. Wysocki" <rafael@kernel.org>,
        Bjorn Helgaas <helgaas@kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Lyude Paul <lyude@redhat.com>,
        "Rafael J . Wysocki" <rjw@rjwysocki.net>,
        Linux PCI <linux-pci@vger.kernel.org>,
        Linux PM <linux-pm@vger.kernel.org>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        nouveau <nouveau@lists.freedesktop.org>,
        Dave Airlie <airlied@gmail.com>,
        Mario Limonciello <Mario.Limonciello@dell.com>
Subject: Re: [PATCH v4] pci: prevent putting nvidia GPUs into lower device
 states on certain intel bridges
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On Wed, Nov 20, 2019 at 12:58:00PM +0100, Karol Herbst wrote:
> overall, what I really want to know is, _why_ does it work on windows?

So do I ;-)

> Or what are we doing differently on Linux so that it doesn't work? If
> anybody has any idea on how we could dig into this and figure it out
> on this level, this would probably allow us to get closer to the root
> cause? no?

Have you tried to use the acpi_rev_override parameter in your system and
does it have any effect?

Also did you try to trace the ACPI _ON/_OFF() methods? I think that
should hopefully reveal something.