linux-kernel - [PATCH] PCI/VGA: Don't assume only VGA device found is the boot VGA device

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Message-ID: <20241014152502.1477809-1-superm1@kernel.org>
Date: Mon, 14 Oct 2024 10:25:02 -0500
From: Mario Limonciello <superm1@...nel.org>
To: Bjorn Helgaas <bhelgaas@...gle.com>
Cc: linux-pci@...r.kernel.org (open list:PCI SUBSYSTEM),
	linux-kernel@...r.kernel.org (open list),
	dri-devel@...ts.freedesktop.org,
	Mario Limonciello <mario.limonciello@....com>,
	Alex Deucher <alexander.deucher@....com>,
	"Luke D . Jones" <luke@...nes.dev>
Subject: [PATCH] PCI/VGA: Don't assume only VGA device found is the boot VGA device

From: Mario Limonciello <mario.limonciello@....com>

The ASUS GA605W has a NVIDIA PCI VGA device and an AMD PCI display device.

```
65:00.0 VGA compatible controller: NVIDIA Corporation AD106M [GeForce RTX 4070 Max-Q / Mobile] (rev a1)
66:00.0 Display controller: Advanced Micro Devices, Inc. [AMD/ATI] Strix [Radeon 880M / 890M] (rev c1)
```

The fallback logic in vga_is_boot_device() flags the NVIDIA dGPU as the
boot VGA device, but really the eDP is connected to the AMD PCI display
device.

Drop this case to avoid marking the NVIDIA dGPU as the boot VGA device.

Suggested-by: Alex Deucher <alexander.deucher@....com>
Reported-by: Luke D. Jones <luke@...nes.dev>
Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/3673
Signed-off-by: Mario Limonciello <mario.limonciello@....com>
---
 drivers/pci/vgaarb.c | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c
index 78748e8d2dba..05ac2b672d4b 100644
--- a/drivers/pci/vgaarb.c
+++ b/drivers/pci/vgaarb.c
@@ -675,13 +675,6 @@ static bool vga_is_boot_device(struct vga_device *vgadev)
 		return true;
 	}
 
-	/*
-	 * Vgadev has neither IO nor MEM enabled.  If we haven't found any
-	 * other VGA devices, it is the best candidate so far.
-	 */
-	if (!boot_vga)
-		return true;
-
 	return false;
 }
 
-- 
2.43.0