linux-kernel - [PATCH v10 3/4] fbcon: Use screen info to find primary device

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Message-ID: <20250811162606.587759-4-superm1@kernel.org>
Date: Mon, 11 Aug 2025 11:26:05 -0500
From: "Mario Limonciello (AMD)" <superm1@...nel.org>
To: David Airlie <airlied@...il.com>,
	Bjorn Helgaas <bhelgaas@...gle.com>
Cc: Alex Deucher <alexander.deucher@....com>,
	Christian König <christian.koenig@....com>,
	Simona Vetter <simona@...ll.ch>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	Maxime Ripard <mripard@...nel.org>,
	Thomas Zimmermann <tzimmermann@...e.de>,
	dri-devel@...ts.freedesktop.org (open list:DRM DRIVERS),
	linux-kernel@...r.kernel.org (open list),
	linux-pci@...r.kernel.org (open list:PCI SUBSYSTEM),
	Daniel Dadap <ddadap@...dia.com>,
	"Mario Limonciello (AMD)" <superm1@...nel.org>
Subject: [PATCH v10 3/4] fbcon: Use screen info to find primary device

On systems with non VGA GPUs fbcon can't find the primary GPU because
video_is_primary_device() only checks the VGA arbiter.

Add a screen info check to video_is_primary_device() so that callers
can get accurate data on such systems.

Reviewed-by: Thomas Zimmermann <tzimmermann@...e.de>
Suggested-by: Thomas Zimmermann <tzimmermann@...e.de>
Suggested-by: Bjorn Helgaas <bhelgaas@...gle.com>
Signed-off-by: Mario Limonciello (AMD) <superm1@...nel.org>
---
v10:
 * Rebase on 6.17-rc1
 * Squash 'fbcon: Stop using screen_info_pci_dev()'
---
 arch/x86/video/video-common.c | 25 ++++++++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

diff --git a/arch/x86/video/video-common.c b/arch/x86/video/video-common.c
index 81fc97a2a837a..e0aeee99bc99e 100644
--- a/arch/x86/video/video-common.c
+++ b/arch/x86/video/video-common.c
@@ -9,6 +9,7 @@
 
 #include <linux/module.h>
 #include <linux/pci.h>
+#include <linux/screen_info.h>
 #include <linux/vgaarb.h>
 
 #include <asm/video.h>
@@ -27,6 +28,11 @@ EXPORT_SYMBOL(pgprot_framebuffer);
 
 bool video_is_primary_device(struct device *dev)
 {
+#ifdef CONFIG_SCREEN_INFO
+	struct screen_info *si = &screen_info;
+	struct resource res[SCREEN_INFO_MAX_RESOURCES];
+	ssize_t i, numres;
+#endif
 	struct pci_dev *pdev;
 
 	if (!dev_is_pci(dev))
@@ -34,7 +40,24 @@ bool video_is_primary_device(struct device *dev)
 
 	pdev = to_pci_dev(dev);
 
-	return (pdev == vga_default_device());
+	if (!pci_is_display(pdev))
+		return false;
+
+	if (pdev == vga_default_device())
+		return true;
+
+#ifdef CONFIG_SCREEN_INFO
+	numres = screen_info_resources(si, res, ARRAY_SIZE(res));
+	for (i = 0; i < numres; ++i) {
+		if (!(res[i].flags & IORESOURCE_MEM))
+			continue;
+
+		if (pci_find_resource(pdev, &res[i]))
+			return true;
+	}
+#endif
+
+	return false;
 }
 EXPORT_SYMBOL(video_is_primary_device);
 
-- 
2.43.0