Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
References: <87ee57c8fu.fsf@turner.link>
 <acd2fd5e-d622-948c-82ef-629a8030c9d8@leemhuis.info>
 <87a6ftk9qy.fsf@dmarc-none.turner.link> <87zgnp96a4.fsf@turner.link>
 <fc2b7593-db8f-091c-67a0-ae5ffce71700@leemhuis.info>
 <CADnq5_Nr5-FR2zP1ViVsD_ZMiW=UHC1wO8_HEGm26K_EG2KDoA@mail.gmail.com>
 <87czkk1pmt.fsf@dmarc-none.turner.link>
 <BYAPR12MB46140BE09E37244AE129C01A975C9@BYAPR12MB4614.namprd12.prod.outlook.com>
 <87sftfqwlx.fsf@dmarc-none.turner.link>
 <BYAPR12MB4614E2CFEDDDEAABBAB986A0975E9@BYAPR12MB4614.namprd12.prod.outlook.com>
 <87ee4wprsx.fsf@turner.link>
 <4b3ed7f6-d2b6-443c-970e-d963066ebfe3@amd.com>
From:   Jim Turner <linuxkernel.foss@dmarc-none.turner.link>
To:     "Lazar, Lijo" <lijo.lazar@amd.com>
Cc:     Alex Deucher <alexdeucher@gmail.com>,
        Thorsten Leemhuis <regressions@leemhuis.info>,
        "Deucher, Alexander" <Alexander.Deucher@amd.com>,
        "regressions@lists.linux.dev" <regressions@lists.linux.dev>,
        "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
        Greg KH <gregkh@linuxfoundation.org>,
        "Pan, Xinhui" <Xinhui.Pan@amd.com>,
        LKML <linux-kernel@vger.kernel.org>,
        "amd-gfx@lists.freedesktop.org" <amd-gfx@lists.freedesktop.org>,
        Alex Williamson <alex.williamson@redhat.com>,
        "Koenig, Christian" <Christian.Koenig@amd.com>
Subject: Re: [REGRESSION] Too-low frequency limit for AMD GPU
 PCI-passed-through to Windows VM
Date:   Sat, 29 Jan 2022 19:25:07 -0500
In-reply-to: <4b3ed7f6-d2b6-443c-970e-d963066ebfe3@amd.com>
Message-ID: <87pmo8r6ob.fsf@turner.link>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

Hi Lijo,

> Specifically, I was looking for any events happening at these two
> places because of the patch-
>
> https://elixir.bootlin.com/linux/v5.16/source/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c#L411
>
> https://elixir.bootlin.com/linux/v5.16/source/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c#L653

I searched the logs generated with all drm debug messages enabled
(drm.debug=0x1ff) for "device_class", "ATCS", "atcs", "ATIF", and
"atif", for both f1688bd69ec4 and f9b7f3703ff9. Other than the few lines
mentioning ATIF from my previous email, there weren't any matches.

Since "device_class" didn't appear in the logs, we know that
`amdgpu_atif_handler` was not called for either version.

I also patched f9b7f3703ff9 to add the line

  DRM_DEBUG_DRIVER("Entered amdgpu_acpi_pcie_performance_request");

at the top (below the variable declarations) of
`amdgpu_acpi_pcie_performance_request`, and then tested again with all
drm debug messages enabled (0x1ff). That debug message didn't show up.

So, `amdgpu_acpi_pcie_performance_request` was not called either, at
least with f9b7f3703ff9. (I didn't try adding this patch to
f1688bd69ec4.)

Would anything else be helpful?

James