Commit 808a4ae5 authored by Kai-Heng Feng's avatar Kai-Heng Feng Committed by Alex Deucher
Browse files

vgaarb: Use ACPI HID name to find integrated GPU 



Commit 3d42f1dd ("vgaarb: Keep adding VGA device in queue") assumes
the first device is an integrated GPU. However, on AMD platforms an
integrated GPU can have higher PCI device number than a discrete GPU.

Integrated GPU on ACPI platform generally has _DOD and _DOS method, so
use that as predicate to find integrated GPU. If the new strategy
doesn't work, fallback to use the first device as boot VGA.

Reviewed-by: default avatarAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: default avatarKai-Heng Feng <kai.heng.feng@canonical.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210519135723.525997-1-kai.heng.feng@canonical.com
parent 3203e497

drivers/gpu/vga/vgaarb.c

+26 −5
Original line number Diff line number Diff line
@@ -50,6 +50,7 @@ 
#include <linux/screen_info.h>

#include <linux/vt.h>

#include <linux/console.h>

#include <linux/acpi.h>



#include <linux/uaccess.h>
@@ -1450,9 +1451,23 @@ static struct miscdevice vga_arb_device = { 
	MISC_DYNAMIC_MINOR, "vga_arbiter", &vga_arb_device_fops

};



#if defined(CONFIG_ACPI)

static bool vga_arb_integrated_gpu(struct device *dev)

{

	struct acpi_device *adev = ACPI_COMPANION(dev);



	return adev && !strcmp(acpi_device_hid(adev), ACPI_VIDEO_HID);

}

#else

static bool vga_arb_integrated_gpu(struct device *dev)

{

	return false;

}

#endif



static void __init vga_arb_select_default_device(void)

{

	struct pci_dev *pdev;

	struct pci_dev *pdev, *found = NULL;

	struct vga_device *vgadev;



#if defined(CONFIG_X86) || defined(CONFIG_IA64)
@@ -1505,20 +1520,26 @@ static void __init vga_arb_select_default_device(void) 
#endif



	if (!vga_default_device()) {

		list_for_each_entry(vgadev, &vga_list, list) {

		list_for_each_entry_reverse(vgadev, &vga_list, list) {

			struct device *dev = &vgadev->pdev->dev;

			u16 cmd;



			pdev = vgadev->pdev;

			pci_read_config_word(pdev, PCI_COMMAND, &cmd);

			if (cmd & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY)) {

				vgaarb_info(dev, "setting as boot device (VGA legacy resources not available)\n");

				vga_set_default_device(pdev);

				found = pdev;

				if (vga_arb_integrated_gpu(dev))

					break;

			}

		}

	}



	if (found) {

		vgaarb_info(&found->dev, "setting as boot device (VGA legacy resources not available)\n");

		vga_set_default_device(found);

		return;

	}



	if (!vga_default_device()) {

		vgadev = list_first_entry_or_null(&vga_list,

						  struct vga_device, list);