At a glance this should(?) only be affecting fbdev=1 (default-off and
marked experimental in nvidia.conf). Compiles fine either way given
the test would've failed resulting in usage being skipped.

NVIDIA is already aware[1] and this should be unnecessary next bumps.
[1] https://github.com/NVIDIA/open-gpu-kernel-modules/pull/692
--- a/kernel/conftest.sh
+++ b/kernel/conftest.sh
@@ -6612,2 +6612,21 @@
 
+        drm_fbdev_ttm_setup)
+            #
+            # Determine whether drm_fbdev_ttm_setup is present.
+            #
+            # Added by commit 9060d7f49376 ("drm/fb-helper: Finish the
+            # generic fbdev emulation") in v4.19.
+            #
+            CODE="
+            #include <drm/drm_fb_helper.h>
+            #if defined(NV_DRM_DRM_FBDEV_TTM_H_PRESENT)
+            #include <drm/drm_fbdev_ttm.h>
+            #endif
+            void conftest_drm_fbdev_ttm_setup(void) {
+                drm_fbdev_ttm_setup();
+            }"
+
+            compile_check_conftest "$CODE" "NV_DRM_FBDEV_TTM_SETUP_PRESENT" "" "functions"
+        ;;
+
         drm_aperture_remove_conflicting_pci_framebuffers)
--- a/kernel/header-presence-tests.mk
+++ b/kernel/header-presence-tests.mk
@@ -17,2 +17,3 @@
   drm/drm_fbdev_generic.h \
+  drm/drm_fbdev_ttm.h \
   drm/drm_framebuffer.h \
--- a/kernel/nvidia-drm/nvidia-drm-drv.c
+++ b/kernel/nvidia-drm/nvidia-drm-drv.c
@@ -75,2 +75,6 @@
 
+#if defined(NV_DRM_DRM_FBDEV_TTM_H_PRESENT)
+#include <drm/drm_fbdev_ttm.h>
+#endif
+
 #include <linux/pci.h>
@@ -1853,3 +1857,7 @@
         }
+#if defined(NV_DRM_FBDEV_TTM_AVAILABLE)
+        drm_fbdev_ttm_setup(dev, 32);
+#else
         drm_fbdev_generic_setup(dev, 32);
+#endif
     }
--- a/kernel/nvidia-drm/nvidia-drm-os-interface.h
+++ b/kernel/nvidia-drm/nvidia-drm-os-interface.h
@@ -60,4 +60,7 @@
 
-#if defined(NV_DRM_FBDEV_GENERIC_SETUP_PRESENT) && defined(NV_DRM_APERTURE_REMOVE_CONFLICTING_PCI_FRAMEBUFFERS_PRESENT)
+#if (defined(NV_DRM_FBDEV_GENERIC_SETUP_PRESENT) || defined(NV_DRM_FBDEV_TTM_SETUP_PRESENT)) && defined(NV_DRM_APERTURE_REMOVE_CONFLICTING_PCI_FRAMEBUFFERS_PRESENT)
 #define NV_DRM_FBDEV_GENERIC_AVAILABLE
+#if defined(NV_DRM_FBDEV_TTM_SETUP_PRESENT)
+#define NV_DRM_FBDEV_TTM_AVAILABLE
+#endif
 #endif
--- a/kernel/nvidia-drm/nvidia-drm-sources.mk
+++ b/kernel/nvidia-drm/nvidia-drm-sources.mk
@@ -69,2 +69,3 @@
 NV_CONFTEST_FUNCTION_COMPILE_TESTS += drm_fbdev_generic_setup
+NV_CONFTEST_FUNCTION_COMPILE_TESTS += drm_fbdev_ttm_setup
 NV_CONFTEST_FUNCTION_COMPILE_TESTS += drm_connector_attach_hdr_output_metadata_property
--- a/kernel-module-source/kernel-open/conftest.sh
+++ b/kernel-module-source/kernel-open/conftest.sh
@@ -6612,2 +6612,21 @@
 
+        drm_fbdev_ttm_setup)
+            #
+            # Determine whether drm_fbdev_ttm_setup is present.
+            #
+            # Added by commit 9060d7f49376 ("drm/fb-helper: Finish the
+            # generic fbdev emulation") in v4.19.
+            #
+            CODE="
+            #include <drm/drm_fb_helper.h>
+            #if defined(NV_DRM_DRM_FBDEV_TTM_H_PRESENT)
+            #include <drm/drm_fbdev_ttm.h>
+            #endif
+            void conftest_drm_fbdev_ttm_setup(void) {
+                drm_fbdev_ttm_setup();
+            }"
+
+            compile_check_conftest "$CODE" "NV_DRM_FBDEV_TTM_SETUP_PRESENT" "" "functions"
+        ;;
+
         drm_aperture_remove_conflicting_pci_framebuffers)
--- a/kernel-module-source/kernel-open/header-presence-tests.mk
+++ b/kernel-module-source/kernel-open/header-presence-tests.mk
@@ -17,2 +17,3 @@
   drm/drm_fbdev_generic.h \
+  drm/drm_fbdev_ttm.h \
   drm/drm_framebuffer.h \
--- a/kernel-module-source/kernel-open/nvidia-drm/nvidia-drm-drv.c
+++ b/kernel-module-source/kernel-open/nvidia-drm/nvidia-drm-drv.c
@@ -75,2 +75,6 @@
 
+#if defined(NV_DRM_DRM_FBDEV_TTM_H_PRESENT)
+#include <drm/drm_fbdev_ttm.h>
+#endif
+
 #include <linux/pci.h>
@@ -1853,3 +1857,7 @@
         }
+#if defined(NV_DRM_FBDEV_TTM_AVAILABLE)
+        drm_fbdev_ttm_setup(dev, 32);
+#else
         drm_fbdev_generic_setup(dev, 32);
+#endif
     }
--- a/kernel-module-source/kernel-open/nvidia-drm/nvidia-drm-os-interface.h
+++ b/kernel-module-source/kernel-open/nvidia-drm/nvidia-drm-os-interface.h
@@ -60,4 +60,7 @@
 
-#if defined(NV_DRM_FBDEV_GENERIC_SETUP_PRESENT) && defined(NV_DRM_APERTURE_REMOVE_CONFLICTING_PCI_FRAMEBUFFERS_PRESENT)
+#if (defined(NV_DRM_FBDEV_GENERIC_SETUP_PRESENT) || defined(NV_DRM_FBDEV_TTM_SETUP_PRESENT)) && defined(NV_DRM_APERTURE_REMOVE_CONFLICTING_PCI_FRAMEBUFFERS_PRESENT)
 #define NV_DRM_FBDEV_GENERIC_AVAILABLE
+#if defined(NV_DRM_FBDEV_TTM_SETUP_PRESENT)
+#define NV_DRM_FBDEV_TTM_AVAILABLE
+#endif
 #endif
--- a/kernel-module-source/kernel-open/nvidia-drm/nvidia-drm-sources.mk
+++ b/kernel-module-source/kernel-open/nvidia-drm/nvidia-drm-sources.mk
@@ -69,2 +69,3 @@
 NV_CONFTEST_FUNCTION_COMPILE_TESTS += drm_fbdev_generic_setup
+NV_CONFTEST_FUNCTION_COMPILE_TESTS += drm_fbdev_ttm_setup
 NV_CONFTEST_FUNCTION_COMPILE_TESTS += drm_connector_attach_hdr_output_metadata_property