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 551ADC433F5 for ; Sat, 8 Jan 2022 02:57:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233390AbiAHC5g (ORCPT ); Fri, 7 Jan 2022 21:57:36 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43648 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230370AbiAHC5g (ORCPT ); Fri, 7 Jan 2022 21:57:36 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2FF82C061574 for ; Fri, 7 Jan 2022 18:57:36 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id C09FF62015 for ; Sat, 8 Jan 2022 02:57:35 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8EBD6C36AE5; Sat, 8 Jan 2022 02:57:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1641610655; bh=FiQX5gMpMaQbrhMlyj4sjZlTDO9MrExzaOZZvHkhlsY=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=ibkiqf/5uynamiAMGLHQ0uMmIvtmHXuFZmL/q30p/z85IC42PUsU7htsV1mP01IMA kRd8P08dKfU+luWb72luLcMm1VqMHcK4mXNUW2Y1NSVeD5etejx2YFvi7kS/mAwVvF Z84KqP6AVhE1GrutpZ6bkUhIFaOKWHfNM0Tq1efK820rQCxln52SnpGih9UuQ2PfrI UWcyNkyeB6S1cXB7icmh+jvJJ4NtObGoXgsBDsBppTtFbwb/KdOke5Cut/OnroNNcy r1v6jPQJlkmR325TdA/ZWXNdOK0CIwN1hQ9DGHowp3DBZLCYUVxenN/yIKL+oVk1Bu n6d1E1NeCxzDQ== Date: Fri, 7 Jan 2022 20:57:32 -0600 From: Bjorn Helgaas To: Lucas De Marchi Cc: x86@kernel.org, Dave Hansen , Ingo Molnar , Thomas Gleixner , Bjorn Helgaas , linux-pci@vger.kernel.org, intel-gfx@lists.freedesktop.org, Ville =?iso-8859-1?Q?Syrj=E4l=E4?= , Matt Roper Subject: Re: [PATCH v3 3/3] x86/quirks: Fix stolen detection with integrated + discrete GPU Message-ID: <20220108025732.GA443415@bhelgaas> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220107210516.907834-3-lucas.demarchi@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Fri, Jan 07, 2022 at 01:05:16PM -0800, Lucas De Marchi wrote: > early_pci_scan_bus() does a depth-first traversal, possibly calling > the quirk functions for each device based on vendor, device and class > from early_qrk table. intel_graphics_quirks() however uses PCI_ANY_ID > and does additional filtering in the quirk. > > If there is an Intel integrated + discrete GPU the quirk may be called > first for the discrete GPU based on the PCI topology. Then we will fail > to reserve the system stolen memory for the integrated GPU, because we > will already have marked the quirk as "applied". > > This was reproduced in a setup with Alderlake-P (integrated) + DG2 > (discrete), with the following PCI topology: > > - 00:01.0 Bridge > `- 03:00.0 DG2 > - 00:02.0 Integrated GPU > > Move the setting of quirk_applied in intel_graphics_quirks() so it's > mark as applied only when we find the integrated GPU based on the > intel_early_ids table. > > Signed-off-by: Lucas De Marchi I don't know the details of stolen memory, but the implementation of this quirk looks good to me. Very nice that it's now very clear exactly what the change is. > --- > > v3: now that we do the refactor before the fix, we can do a single line > change to fix intel_graphics_quirks(). Also, we don't change > intel_graphics_stolen() anymore as we did in v2: we don't have to check > other devices anymore if there was a previous match causing > intel_graphics_stolen() to be called (there can only be one integrated > GPU reserving the stolen memory). > > arch/x86/kernel/early-quirks.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kernel/early-quirks.c b/arch/x86/kernel/early-quirks.c > index df34963e23bf..932f9087c324 100644 > --- a/arch/x86/kernel/early-quirks.c > +++ b/arch/x86/kernel/early-quirks.c > @@ -609,8 +609,6 @@ static void __init intel_graphics_quirks(int num, int slot, int func) > if (quirk_applied) > return; > > - quirk_applied = true; > - > device = read_pci_config_16(num, slot, func, PCI_DEVICE_ID); > > for (i = 0; i < ARRAY_SIZE(intel_early_ids); i++) { > @@ -623,6 +621,8 @@ static void __init intel_graphics_quirks(int num, int slot, int func) > > intel_graphics_stolen(num, slot, func, early_ops); > > + quirk_applied = true; > + > return; > } > } > -- > 2.34.1 >