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 8D91BC433F5 for ; Tue, 1 Feb 2022 15:46:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240555AbiBAPqm (ORCPT ); Tue, 1 Feb 2022 10:46:42 -0500 Received: from mga04.intel.com ([192.55.52.120]:26867 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240521AbiBAPqj (ORCPT ); Tue, 1 Feb 2022 10:46:39 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1643730399; x=1675266399; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=d9eKHUfVREYlEXOMy6/dbAqRNvB0R5n8Xjyt6b1+6HE=; b=d/Jx2ga3CIukNweVndQXc/EMFAs7jYvJantwB9CJlSKeXH/GB8GOCm0B V5VsimeUIvRH+03XBD4i1yACVNTfVyeOqG8J6gTNLzR1n2gzkUvOzBsg0 xspWxa0tAwlexd9AiKvck026IZ9J4RB4eTq+7PLjbPDAdqdKRaJiZKUpM 3vvcvi971xvnL4HNDWeI4VEDWiar+ravQlKux4Xbk5jQuP+7akcMH/fXi 6U8qwVh4pGuhdrsuF75P3HQeIonbhMRde2AO2749jKP3hOA/EGqXxo6nr tSDN76Z4o1ChYcaQJXC7crOnf59tZx3okshUL/McUB+vXWf2B8qwH2Q0P Q==; X-IronPort-AV: E=McAfee;i="6200,9189,10244"; a="246550085" X-IronPort-AV: E=Sophos;i="5.88,334,1635231600"; d="scan'208";a="246550085" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Feb 2022 07:46:38 -0800 X-IronPort-AV: E=Sophos;i="5.88,334,1635231600"; d="scan'208";a="537853590" Received: from tveit-mobl1.ger.corp.intel.com (HELO [10.252.37.11]) ([10.252.37.11]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Feb 2022 07:46:36 -0800 Message-ID: Date: Tue, 1 Feb 2022 16:46:33 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Firefox/91.0 Thunderbird/91.5.1 Subject: Re: [PATCH v8 00/10] vgaarb: Rework default VGA device selection Content-Language: en-US To: Bjorn Helgaas , David Airlie , Daniel Vetter , Maxime Ripard , Thomas Zimmermann Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Bjorn Helgaas , Xuefeng Li , Huacai Chen References: <20220131222342.GA517488@bhelgaas> From: Maarten Lankhorst In-Reply-To: <20220131222342.GA517488@bhelgaas> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hey,   Op 31-01-2022 om 23:23 schreef Bjorn Helgaas: > [+to Maarten, Maxime, Thomas; beginning of thread: > https://lore.kernel.org/r/20220106000658.243509-1-helgaas@kernel.org] > > On Wed, Jan 05, 2022 at 06:06:48PM -0600, Bjorn Helgaas wrote: >> From: Bjorn Helgaas >> >> Current default VGA device selection fails in some cases because part of it >> is done in the vga_arb_device_init() subsys_initcall, and some arches >> enumerate PCI devices in pcibios_init(), which runs *after* that. > Where are we at with this series? Is there anything I can do to move > it forward? > > Bjorn Hi Bjorn, I'm afraid that I don't understand the vga arbiter or the vga code well enough to review. Could you perhaps find someone who could review? I see Chen wrote some patches and tested, so perhaps they could? ~Maarten >> For example: >> >> - On BMC system, the AST2500 bridge [1a03:1150] does not implement >> PCI_BRIDGE_CTL_VGA. This is perfectly legal but means the legacy VGA >> resources won't reach downstream devices unless they're included in the >> usual bridge windows. >> >> - vga_arb_select_default_device() will set a device below such a bridge >> as the default VGA device as long as it has PCI_COMMAND_IO and >> PCI_COMMAND_MEMORY enabled. >> >> - vga_arbiter_add_pci_device() is called for every VGA device, either at >> boot-time or at hot-add time, and it will also set the device as the >> default VGA device, but ONLY if all bridges leading to it implement >> PCI_BRIDGE_CTL_VGA. >> >> - This difference between vga_arb_select_default_device() and >> vga_arbiter_add_pci_device() means that a device below an AST2500 or >> similar bridge can only be set as the default if it is enumerated >> before vga_arb_device_init(). >> >> - On ACPI-based systems, PCI devices are enumerated by acpi_init(), which >> runs before vga_arb_device_init(). >> >> - On non-ACPI systems, like on MIPS system, they are enumerated by >> pcibios_init(), which typically runs *after* vga_arb_device_init(). >> >> This series consolidates all the default VGA device selection in >> vga_arbiter_add_pci_device(), which is always called after enumerating a >> PCI device. >> >> Almost all the work here is Huacai's. I restructured it a little bit and >> added a few trivial patches on top. >> >> I'd like to move vgaarb.c to drivers/pci eventually, but there's another >> initcall ordering snag that needs to be resolved first, so this leaves >> it where it is. >> >> Bjorn >> >> Version history: >> V0 original implementation as final quirk to set default device. >> https://lore.kernel.org/r/20210514080025.1828197-6-chenhuacai@loongson.cn >> >> V1 rework vgaarb to do all default device selection in >> vga_arbiter_add_pci_device(). >> https://lore.kernel.org/r/20210705100503.1120643-1-chenhuacai@loongson.cn >> >> V2 move arbiter to PCI subsystem, fix nits. >> https://lore.kernel.org/r/20210722212920.347118-1-helgaas@kernel.org >> >> V3 rewrite the commit log of the last patch (which is also summarized >> by Bjorn). >> https://lore.kernel.org/r/20210820100832.663931-1-chenhuacai@loongson.cn >> >> V4 split the last patch to two steps. >> https://lore.kernel.org/r/20210827083129.2781420-1-chenhuacai@loongson.cn >> >> V5 split Patch-9 again and sort the patches. >> https://lore.kernel.org/r/20210911093056.1555274-1-chenhuacai@loongson.cn >> >> V6 split Patch-5 again and sort the patches again. >> https://lore.kernel.org/r/20210916082941.3421838-1-chenhuacai@loongson.cn >> >> V7 stop moving vgaarb to drivers/pci because of ordering issues with >> misc_init(). >> https://lore.kernel.org/r/20211015061512.2941859-1-chenhuacai@loongson.cn >> https://lore.kernel.org/r/CAAhV-H7FhAjM-Ha42Z1dLrE4PvC9frfyeU27KHWcyWKkMftEsA@mail.gmail.com >> >> >> Bjorn Helgaas (8): >> vgaarb: Factor out vga_select_framebuffer_device() >> vgaarb: Factor out default VGA device selection >> vgaarb: Move framebuffer detection to ADD_DEVICE path >> vgaarb: Move non-legacy VGA detection to ADD_DEVICE path >> vgaarb: Move disabled VGA device detection to ADD_DEVICE path >> vgaarb: Remove empty vga_arb_device_card_gone() >> vgaarb: Use unsigned format string to print lock counts >> vgaarb: Replace full MIT license text with SPDX identifier >> >> Huacai Chen (2): >> vgaarb: Move vga_arb_integrated_gpu() earlier in file >> vgaarb: Log bridge control messages when adding devices >> >> drivers/gpu/vga/vgaarb.c | 311 +++++++++++++++++++-------------------- >> 1 file changed, 154 insertions(+), 157 deletions(-) >> >> -- >> 2.25.1 >>