On Thu, Jul 17, 2025 at 12:38:12PM -0500, Mario Limonciello wrote:
> From: Mario Limonciello <mario.limoncie...@amd.com>
>
> On systems with multiple GPUs there can be uncertainty which GPU is the
> primary one used to drive the display at bootup. In some desktop
> environments this can lead to increased power consumption because
> secondary GPUs may be used for rendering and never go to a low power
> state. 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.
> +What: /sys/bus/pci/devices/.../boot_display
> +Date: October 2025
> +Contact: Linux PCI developers <linux-...@vger.kernel.org>
> +Description:
> + This file indicates that displays connected to the device were
> + used to display the boot sequence. If a display connected to
> + the device was used to display the boot sequence the file will
> + be present and contain "1".
> 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);
In addition to Mani's question about whether /sys/bus/pci/ is the
right place for this (which is a very good question), it's also been
pointed out to me that we've been trying to get rid of
pci_create_sysfs_dev_files() for years.
If it's possible to make this a static attribute that would be much,
much cleaner.
> + 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
>
