From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 149B8C433FE for ; Mon, 14 Mar 2022 02:53:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229645AbiCNCyw (ORCPT ); Sun, 13 Mar 2022 22:54:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58924 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232847AbiCNCyv (ORCPT ); Sun, 13 Mar 2022 22:54:51 -0400 Received: from out2-smtp.messagingengine.com (out2-smtp.messagingengine.com [66.111.4.26]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F1B4C3A71F; Sun, 13 Mar 2022 19:53:41 -0700 (PDT) Received: from compute3.internal (compute3.nyi.internal [10.202.2.43]) by mailout.nyi.internal (Postfix) with ESMTP id 8DFD85C0112; Sun, 13 Mar 2022 22:53:39 -0400 (EDT) Received: from mailfrontend2 ([10.202.2.163]) by compute3.internal (MEProxy); Sun, 13 Mar 2022 22:53:39 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=turner.link; h= cc:cc:content-type:date:date:from:from:in-reply-to:in-reply-to :message-id:mime-version:references:reply-to:sender:subject :subject:to:to; s=fm2; bh=mk9hxX9pdpaTprhpWtmYamoWls5zOpQ2mqbAXe YUr48=; b=a5KXI2BZUJhiA3fDQXwftBtJeQjfqVmIUk8KXXTvsbGB7pnI99fXuT ZqzBOPwaDNwAPweuJAE/hKTYUob78wbwev83/J/Viqsv+SOPjGIPfqQqiIJ/EqyD mZcR12Zt8dnNRCI4T9QXJKiFg4PlCLTViM5WBkhrHVO042BR50fVpbmt0lScv7Dw SNB8WqIVDS/KQgfKJlNKERCJvOKHfW5+flWckvaPDCe+1dq51PzpyYM5Zir2Tbkl yIcybJjvd4NVtj1/lnQ34GJTOGIRMsbSiTRyDAvKFoUZVEuYvE6MSk6Ze9UpfcH3 hVQqoKPHht3FfOQrt3PkFAkqc0+Ok9sQ== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-type:date:date:from:from :in-reply-to:in-reply-to:message-id:mime-version:references :reply-to:sender:subject:subject:to:to:x-me-proxy:x-me-proxy :x-me-sender:x-me-sender:x-sasl-enc; s=fm2; bh=mk9hxX9pdpaTprhpW tmYamoWls5zOpQ2mqbAXeYUr48=; b=ENWQVZ/6OdSptCSfVJ9UQ4r1zW+lXOx/8 4hzi6mFnY8SVDSK51blxdzEyt3JIxXyyF0ZGybf7UQnpAsZZDOtSxxa+CM70TvNh C6Z15dLy/cRj6qY4E73Re6K7d/4G1o/KsQvc4t+Q+XnmPWtKLsP9Fj5Kjsd3Gx8G D0YcmOGF3ICYXR7GS6fNziTvbVebiChvxMCHsGslkItQ4KFY8H6sypJAHcSdiuc6 C5mEAWwmC8w4y33hGjTX7RJlOSqn2ebiZ5iTXK+CNz2ivgm29jq4qG9O68limXpm Ki79dwLbg2XlVbr0yx2Nx/56TiU4E7O6XAQcLJfmqMJ4WUuVKDDvA== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvvddruddvjedgheduucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmne cujfgurhepfhfhvffuffgjkfggtgesthdtredttddttdenucfhrhhomheplfgrmhgvshcu vfhurhhnvghruceolhhinhhugihkvghrnhgvlhdrfhhoshhssegumhgrrhgtqdhnohhnvg drthhurhhnvghrrdhlihhnkheqnecuggftrfgrthhtvghrnhepfffhveeugfevteeileej vdeltdegtdeggfeujefgveekueevkeehheehffduleevnecuffhomhgrihhnpegrrhgthh hlihhnuhigrdhorhhgnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehmrghi lhhfrhhomheplhhinhhugihkvghrnhgvlhdrfhhoshhssegumhgrrhgtqdhnohhnvgdrth hurhhnvghrrdhlihhnkh X-ME-Proxy: Received: by mail.messagingengine.com (Postfix) with ESMTPA; Sun, 13 Mar 2022 22:53:39 -0400 (EDT) References: <87ee57c8fu.fsf@turner.link> <87a6ftk9qy.fsf@dmarc-none.turner.link> <87zgnp96a4.fsf@turner.link> <87czkk1pmt.fsf@dmarc-none.turner.link> <87sftfqwlx.fsf@dmarc-none.turner.link> <87ee4wprsx.fsf@turner.link> <4b3ed7f6-d2b6-443c-970e-d963066ebfe3@amd.com> <87pmo8r6ob.fsf@turner.link> <5a68afe4-1e9e-c683-e06d-30afc2156f14@leemhuis.info> <87pmnnpmh5.fsf@dmarc-none.turner.link> <092b825a-10ff-e197-18a1-d3e3a097b0e3@leemhuis.info> <877d96to55.fsf@dmarc-none.turner.link> From: James Turner To: Thorsten Leemhuis Cc: Alex Deucher , "Lazar, Lijo" , "Deucher, Alexander" , "regressions@lists.linux.dev" , "kvm@vger.kernel.org" , Greg KH , "Pan, Xinhui" , LKML , "amd-gfx@lists.freedesktop.org" , Alex Williamson , "Koenig, Christian" Subject: Re: [REGRESSION] Too-low frequency limit for AMD GPU PCI-passed-through to Windows VM Date: Sun, 13 Mar 2022 14:33:41 -0400 In-reply-to: <877d96to55.fsf@dmarc-none.turner.link> Message-ID: <87lexdw8gd.fsf@turner.link> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Hi all, I've confirmed that changing the `amdgpu_atif_pci_probe_handle` function to do nothing does make the GPU work properly in the VM. I started with f9b7f3703ff9 ("drm/amdgpu/acpi: make ATPX/ATCS structures global (v2)") and changed the function implementation to: static bool amdgpu_atif_pci_probe_handle(struct pci_dev *pdev) { DRM_DEBUG_DRIVER("Entered amdgpu_atif_pci_probe_handle"); return false; } With that change, the GPU works properly in the VM. I'm not sure where to go from here. This issue isn't much of a concern for me anymore, since blacklisting `amdgpu` works for my machine. At this point, my understanding is that the root problem needs to be fixed in AMD's Windows GPU driver or Dell's firmware, not the Linux kernel. If any of the AMD developers on this thread would like to forward it to the AMD Windows driver team, I'd be happy to work with AMD to fix the issue properly. I've added a mention of this issue and workaround to the [Arch Wiki][1] to make it more discoverable. If anyone has a better place to document this, please let me know. Thank you all for your help on this. [1]: https://wiki.archlinux.org/title/PCI_passthrough_via_OVMF#Too-low_frequency_limit_for_AMD_GPU_passed-through_to_virtual_machine James