From patchwork Fri Oct 15 06:15:01 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Huacai Chen X-Patchwork-Id: 12560055 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AF3B0C433EF for ; Fri, 15 Oct 2021 06:15:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8A9C260F59 for ; Fri, 15 Oct 2021 06:15:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232267AbhJOGRq (ORCPT ); Fri, 15 Oct 2021 02:17:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:60496 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230244AbhJOGRq (ORCPT ); Fri, 15 Oct 2021 02:17:46 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 12C4761090; Fri, 15 Oct 2021 06:15:37 +0000 (UTC) From: Huacai Chen To: David Airlie , Daniel Vetter , Bjorn Helgaas Cc: linux-pci@vger.kernel.org, dri-devel@lists.freedesktop.org, Xuefeng Li , Huacai Chen , Huacai Chen Subject: [PATCH V7 00/11] PCI/VGA: Rework default VGA device selection Date: Fri, 15 Oct 2021 14:15:01 +0800 Message-Id: <20211015061512.2941859-1-chenhuacai@loongson.cn> X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org My original work is at [1]. Current default VGA device selection fails in some cases: - On BMC system, the AST2500 bridge [1a03:1150] does not implement PCI_BRIDGE_CTL_VGA [1]. 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(). So I made vga_arb_update_default_device() to replace the current vga_ arb_select_default_device(), which will be call from vga_arbiter_add_ pci_device(), set the default device even if it does not own the VGA resources because an upstream bridge doesn't implement PCI_BRIDGE_CTL_ VGA. And the default VGA device is updated if a better one is found (device with legacy resources enabled is better, device owns the firmware framebuffer is even better). Bjorn do some rework and extension in V2. It moves the VGA arbiter to the PCI subsystem, fixes a few nits, and breaks a few pieces to make the main patch a little smaller. V3 rewrite the commit log of the last patch (which is also summarized by Bjorn). V4 split the last patch to two steps. V5 split Patch-9 again and sort the patches. V6 split Patch-5 again and sort the patches again. V7 stop moving vgaarb to drivers/pci because it cause new problems. All comments welcome! [1] https://lore.kernel.org/dri-devel/20210705100503.1120643-1-chenhuacai@loongson.cn/ Huacai Chen (8): PCI/VGA: Prefer vga_default_device() PCI/VGA: Move vga_arb_integrated_gpu() earlier in file PCI/VGA: Split out vga_arb_update_default_device() PCI/VGA: Prefer VGA device with legacy I/O enabled PCI/VGA: Prefer VGA device belongs to integrated GPU PCI/VGA: Prefer VGA device owns the firmware framebuffer PCI/VGA: Remove vga_arb_select_default_device() PCI/VGA: Log bridge control messages when adding devices Bjorn Helgaas (3): PCI/VGA: Remove empty vga_arb_device_card_gone() PCI/VGA: Use unsigned format string to print lock counts PCI/VGA: Replace full MIT license text with SPDX identifier Signed-off-by: Huacai Chen Signed-off-by: Bjorn Helgaas --- drivers/gpu/vga/Kconfig | 19 --- drivers/gpu/vga/Makefile | 1 - drivers/pci/Kconfig | 19 +++ drivers/pci/Makefile | 1 + 4 files changed, 126 insertions(+), 183 deletions(-) -- 2.27.0