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 2D3B9C433EF for ; Mon, 31 Jan 2022 22:23:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233207AbiAaWXr (ORCPT ); Mon, 31 Jan 2022 17:23:47 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33906 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229658AbiAaWXp (ORCPT ); Mon, 31 Jan 2022 17:23:45 -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 982CBC061714; Mon, 31 Jan 2022 14:23:45 -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 2F613615C6; Mon, 31 Jan 2022 22:23:45 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3B9D5C340E8; Mon, 31 Jan 2022 22:23:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1643667824; bh=0Y3rqgHlAMjH8w1RLY+36FufBDg9B2bU0SqT42dDkig=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=VJGnBnmU3SXGd+G8IsHvhCOl83XvQO75dgqmOmMAvwsNtgc7jUQIDgXypI4KMnd6O Bm8HkYi16UX7+jZJu+BTLKhPD1I2BXJ5tvRSymVdDkzsYffNO+Rg9LNRsuS1YbM1bG kgivmCN/59omZJUGTrFfb3YHyg4PpE4QXH8Pq91DaF7XgqbU69sv5u/CIvPX+orVIJ EPuv0ZngdPeFm7gHFKwl4Xt3DkT+0m1g8rsYaSqJ7dsn0zdxNvPNEPIWrw33fJFm/s fnAxKaPT4d+di9wmjOfNwKLI61t3b+6q76AIr+03hGGZv7IIiMazLbJy1RRaXb1xrW RJpMQ65e/JnFA== Date: Mon, 31 Jan 2022 16:23:42 -0600 From: Bjorn Helgaas To: David Airlie , Daniel Vetter , Maarten Lankhorst , 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 Subject: Re: [PATCH v8 00/10] vgaarb: Rework default VGA device selection Message-ID: <20220131222342.GA517488@bhelgaas> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220106000658.243509-1-helgaas@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [+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 > 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 >