From: Ian Forbes <ian.forbes@broadcom.com>
Date: Fri, 14 Nov 2025 20:37:03 +0000 (-0600)
Subject: drm/vmwgfx: Fix KMS with 3D on HW version 10
X-Git-Tag: v6.19-rc6~20^2^2~14
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d9186faeae6efb7d0841a5e8eb213ff4c7966614;p=thirdparty%2Flinux.git

drm/vmwgfx: Fix KMS with 3D on HW version 10

HW version 10 does not have GB Surfaces so there is no backing buffer for
surface backed FBs. This would result in a nullptr dereference and crash
the driver causing a black screen.

Fixes: 965544150d1c ("drm/vmwgfx: Refactor cursor handling")
Signed-off-by: Ian Forbes <ian.forbes@broadcom.com>
Reviewed-by: Zack Rusin <zack.rusin@broadcom.com>
Signed-off-by: Zack Rusin <zack.rusin@broadcom.com>
Link: https://patch.msgid.link/20251114203703.1946616-1-ian.forbes@broadcom.com
---

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
index d32ce1cb579e..bc51b5d55e38 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
@@ -766,13 +766,15 @@ err_out:
 		return ERR_PTR(ret);
 	}
 
-	ttm_bo_reserve(&bo->tbo, false, false, NULL);
-	ret = vmw_bo_dirty_add(bo);
-	if (!ret && surface && surface->res.func->dirty_alloc) {
-		surface->res.coherent = true;
-		ret = surface->res.func->dirty_alloc(&surface->res);
+	if (bo) {
+		ttm_bo_reserve(&bo->tbo, false, false, NULL);
+		ret = vmw_bo_dirty_add(bo);
+		if (!ret && surface && surface->res.func->dirty_alloc) {
+			surface->res.coherent = true;
+			ret = surface->res.func->dirty_alloc(&surface->res);
+		}
+		ttm_bo_unreserve(&bo->tbo);
 	}
-	ttm_bo_unreserve(&bo->tbo);
 
 	return &vfb->base;
 }