From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8EA8F1DE2D7; Fri, 27 Jun 2025 04:31:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750998698; cv=none; b=fhRJc5H24s2nricNm5HKMnjAQNL9gi1etZ1+MwpmUK0wCS39p/Pq9fhiMRICrr5DY3C15FeAAwS9t2+Y1Cn+P5Bjewifd6MwhX11PHU1T0FB+jUR8ZSzRTYif+Z6y3DQg4wWlqlQtsHlM03CB4jPoaTxasQXbayxoyben2D4Iwk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750998698; c=relaxed/simple; bh=wM5TClw82+g+f6tTVZpsOWcLA2SCBE+v6qAmnJL26dg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=E71NNGVVYD4wFnP0OCiGv9gADJDygJPl1z024DtlhrEx+9XYbIxUO/ShB8ld7Irg/IVccYrtpxxkBVPGTWLnFR56jGtvwuOV1LEzabZtRCPNZsfpISzigrkArFc3n7Ws2u1H88H2zzVSNkhaVGkz5xmsfljZeqUYOT0+Z58iqeI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=TyBp7Exh; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="TyBp7Exh" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3DC04C4CEEB; Fri, 27 Jun 2025 04:31:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1750998698; bh=wM5TClw82+g+f6tTVZpsOWcLA2SCBE+v6qAmnJL26dg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TyBp7Exh1zUlLHHkHOA8PkAI5rInJOVDVZwtpuqi67FZ4fdGvEHRo6GMm5D1DlpKy d1EeX3yqogTDFj0B0IYKcsxtuZDBpT8Gx5h8KaZV6k4GFtPjEmn3D+Gv80L4uS92H7 oQ3KJAPnROQReELH/VMeLqO7/fZOxgrwjBYcQ8Ckd/viHQzGw3bURRXjezKAVDmwqY SBKQBOujgECCL6MiHhRwja7T/GkmdLA4NHAm677pKzhmZXZ7+CK0DGfyToQ21grjMX pKXGUt0f4do2wBJQ5YgznQPO1zOVTqaajqY/66jnb6HG3y8StmRxs0ckNlQY+Rn85g TBj6z0uy0uHcQ== From: Mario Limonciello To: Bjorn Helgaas Cc: Alex Deucher , =?UTF-8?q?Christian=20K=C3=B6nig?= , David Airlie , Simona Vetter , Lukas Wunner , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Woodhouse , Lu Baolu , Joerg Roedel , Will Deacon , Robin Murphy , Alex Williamson , Jaroslav Kysela , Takashi Iwai , dri-devel@lists.freedesktop.org (open list:DRM DRIVERS), linux-kernel@vger.kernel.org (open list), iommu@lists.linux.dev (open list:INTEL IOMMU (VT-d)), linux-pci@vger.kernel.org (open list:PCI SUBSYSTEM), kvm@vger.kernel.org (open list:VFIO DRIVER), linux-sound@vger.kernel.org (open list:SOUND), Daniel Dadap , Mario Limonciello Subject: [PATCH v6 9/9] PCI: Add a new 'boot_display' attribute Date: Thu, 26 Jun 2025 23:31:08 -0500 Message-ID: <20250627043108.3141206-10-superm1@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20250627043108.3141206-1-superm1@kernel.org> References: <20250627043108.3141206-1-superm1@kernel.org> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Mario Limonciello On systems with multiple GPUs there can be uncertainty which GPU is the primary one used to drive the display at bootup. In order to disambiguate this add a new sysfs attribute 'boot_display' that uses the output of video_is_primary_device() to populate whether a PCI device was used for driving the display. Signed-off-by: Mario Limonciello --- v6: * Only show for the device that is boot display * Only create after PCI device sysfs files are initialized to ensure that resources are ready. v4: * new patch --- Documentation/ABI/testing/sysfs-bus-pci | 8 +++++ drivers/pci/pci-sysfs.c | 46 +++++++++++++++++++++++++ 2 files changed, 54 insertions(+) diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci index 69f952fffec72..8b455b1a58852 100644 --- a/Documentation/ABI/testing/sysfs-bus-pci +++ b/Documentation/ABI/testing/sysfs-bus-pci @@ -612,3 +612,11 @@ Description: # ls doe_features 0001:01 0001:02 doe_discovery + +What: /sys/bus/pci/devices/.../boot_display +Date: October 2025 +Contact: Linux PCI developers +Description: + This file indicates the device was used as a boot + display. If the device was used as the boot display, the file + will be present and contain "1". diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index 268c69daa4d57..cc766461de1da 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -30,6 +30,7 @@ #include #include #include +#include #include "pci.h" #ifndef ARCH_PCI_DEV_GROUPS @@ -679,6 +680,13 @@ const struct attribute_group *pcibus_groups[] = { NULL, }; +static ssize_t boot_display_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + return sysfs_emit(buf, "1\n"); +} +static DEVICE_ATTR_RO(boot_display); + static ssize_t boot_vga_show(struct device *dev, struct device_attribute *attr, char *buf) { @@ -1246,6 +1254,37 @@ static int pci_create_attr(struct pci_dev *pdev, int num, int write_combine) return 0; } +/** + * pci_create_boot_display_file - create a file in sysfs for @dev + * @pdev: dev in question + * + * Creates a file `boot_display` in sysfs for the PCI device @pdev + * if it is the boot display device. + */ +static int pci_create_boot_display_file(struct pci_dev *pdev) +{ +#ifdef CONFIG_VIDEO + if (video_is_primary_device(&pdev->dev)) + return sysfs_create_file(&pdev->dev.kobj, &dev_attr_boot_display.attr); +#endif + return 0; +} + +/** + * pci_remove_boot_display_file - remove the boot display file for @dev + * @pdev: dev in question + * + * Removes the file `boot_display` in sysfs for the PCI device @pdev + * if it is the boot display device. + */ +static void pci_remove_boot_display_file(struct pci_dev *pdev) +{ +#ifdef CONFIG_VIDEO + if (video_is_primary_device(&pdev->dev)) + sysfs_remove_file(&pdev->dev.kobj, &dev_attr_boot_display.attr); +#endif +} + /** * pci_create_resource_files - create resource files in sysfs for @dev * @pdev: dev in question @@ -1654,9 +1693,15 @@ static const struct attribute_group pci_dev_resource_resize_group = { int __must_check pci_create_sysfs_dev_files(struct pci_dev *pdev) { + int retval; + if (!sysfs_initialized) return -EACCES; + retval = pci_create_boot_display_file(pdev); + if (retval) + return retval; + return pci_create_resource_files(pdev); } @@ -1671,6 +1716,7 @@ void pci_remove_sysfs_dev_files(struct pci_dev *pdev) if (!sysfs_initialized) return; + pci_remove_boot_display_file(pdev); pci_remove_resource_files(pdev); } -- 2.43.0