queue-6.18/drm-amdgpu-make-mac-fb-workaround-generic.patch

From c7f44ec5c4ec760e74351f1843dcb8322f67cbf6 Mon Sep 17 00:00:00 2001
From: Alex Deucher <alexander.deucher@amd.com>
Date: Fri, 25 Sep 2026 09:16:26 -0400
Subject: drm/amdgpu: make Mac FB workaround generic
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

From: Alex Deucher <alexander.deucher@amd.com>

commit c7f44ec5c4ec760e74351f1843dcb8322f67cbf6 upstream.

Rather than adding a case of every chip where this is seen
just check if the FB is at 0 and the ssid is apple.  This
should cover all chips which fall into this case.

Tested-by: Ayhan Çiçek <ayhancicek@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit c54e4d10507722398dc90cf3c532e50b86cf425a)
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c |   17 +++++++----------
 1 file changed, 7 insertions(+), 10 deletions(-)

--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c
@@ -1022,20 +1022,17 @@ void amdgpu_gmc_get_vbios_allocations(st
 	case CHIP_RENOIR:
 		adev->mman.keep_stolen_vga_memory = true;
 		break;
-	case CHIP_POLARIS10:
-	case CHIP_POLARIS11:
-	case CHIP_POLARIS12:
-		/* MacBookPros with switchable graphics put VRAM at 0 when
-		 * the iGPU is enabled which results in cursor issues if
-		 * the cursor ends up at 0.  Reserve vram at 0 in that case.
-		 */
-		if (adev->gmc.vram_start == 0)
-			adev->mman.keep_stolen_vga_memory = true;
-		break;
 	default:
 		adev->mman.keep_stolen_vga_memory = false;
 		break;
 	}
+	/* MacBookPros with switchable graphics put VRAM at 0 when
+	 * the iGPU is enabled which results in cursor issues if
+	 * the cursor ends up at 0.  Reserve vram at 0 in that case.
+	 */
+	if ((adev->pdev->subsystem_vendor == PCI_VENDOR_ID_APPLE) &&
+	    (adev->gmc.vram_start == 0))
+		adev->mman.keep_stolen_vga_memory = true;
 
 	if (amdgpu_sriov_vf(adev) ||
 	    !amdgpu_device_has_display_hardware(adev)) {