diff --git a/gfx/config/gfxVars.h b/gfx/config/gfxVars.h
index 694bbeb76323..37352d050b3d 100644
--- a/gfx/config/gfxVars.h
+++ b/gfx/config/gfxVars.h
@@ -58,6 +58,7 @@ class gfxVarReceiver;
   _(WebRenderDebugFlags, int32_t, 0)                               \
   _(WebRenderBatchingLookback, int32_t, 10)                        \
   _(UseSoftwareWebRender, bool, false)                             \
+  _(AllowSoftwareWebRenderD3D11, bool, false)                      \
   _(ScreenDepth, int32_t, 0)                                       \
   _(GREDirectory, nsString, nsString())                            \
   _(ProfDirectory, nsString, nsString())                           \
diff --git a/gfx/layers/LayersTypes.cpp b/gfx/layers/LayersTypes.cpp
index 62be26755ad1..c36511e8c445 100644
--- a/gfx/layers/LayersTypes.cpp
+++ b/gfx/layers/LayersTypes.cpp
@@ -39,7 +39,7 @@ const char* GetLayersBackendName(LayersBackend aBackend) {
       MOZ_ASSERT(gfx::gfxVars::UseWebRender());
       if (gfx::gfxVars::UseSoftwareWebRender()) {
 #ifdef XP_WIN
-        if (StaticPrefs::gfx_webrender_software_d3d11_AtStartup() &&
+        if (gfx::gfxVars::AllowSoftwareWebRenderD3D11() &&
             gfx::gfxConfig::IsEnabled(gfx::Feature::D3D11_COMPOSITING)) {
           return "webrender_software_d3d11";
         }
diff --git a/gfx/thebes/gfxPlatform.cpp b/gfx/thebes/gfxPlatform.cpp
index 996c57dbcc20..7ff572e51c72 100644
--- a/gfx/thebes/gfxPlatform.cpp
+++ b/gfx/thebes/gfxPlatform.cpp
@@ -2705,6 +2705,9 @@ void gfxPlatform::InitWebRenderConfig() {
   if (gfxConfig::IsEnabled(Feature::WEBRENDER_DCOMP_PRESENT)) {
     gfxVars::SetUseWebRenderDCompWin(true);
   }
+  if (StaticPrefs::gfx_webrender_software_d3d11_AtStartup()) {
+    gfxVars::SetAllowSoftwareWebRenderD3D11(true);
+  }
   if (Preferences::GetBool("gfx.webrender.dcomp-video-overlay-win", false)) {
     if (IsWin10AnniversaryUpdateOrLater() &&
         gfxConfig::IsEnabled(Feature::WEBRENDER_COMPOSITOR)) {
@@ -3313,7 +3316,7 @@ bool gfxPlatform::FallbackFromAcceleration(FeatureStatus aStatus,
   // Before we disable D3D11 and HW_COMPOSITING, we should check if we can
   // fallback from WebRender to Software WebRender + D3D11 compositing.
   if (StaticPrefs::gfx_webrender_fallback_software_d3d11_AtStartup() &&
-      StaticPrefs::gfx_webrender_software_d3d11_AtStartup() &&
+      gfxVars::AllowSoftwareWebRenderD3D11() &&
       gfxConfig::IsEnabled(Feature::WEBRENDER_SOFTWARE) &&
       gfxConfig::IsEnabled(Feature::D3D11_COMPOSITING) &&
       gfxVars::UseWebRender() && !gfxVars::UseSoftwareWebRender()) {
@@ -3323,6 +3326,15 @@ bool gfxPlatform::FallbackFromAcceleration(FeatureStatus aStatus,
     return true;
   }
 
+  if (StaticPrefs::gfx_webrender_fallback_software_d3d11_AtStartup() &&
+      gfxVars::AllowSoftwareWebRenderD3D11() &&
+      gfxVars::UseSoftwareWebRender()) {
+    // Fallback from Software WebRender + D3D11 to Software WebRender.
+    gfxCriticalNote << "Fallback SW-WR + D3D11 to SW-WR";
+    gfxVars::SetAllowSoftwareWebRenderD3D11(false);
+    return true;
+  }
+
   // We aren't using Software WebRender + D3D11 compositing, so turn off the
   // D3D11 and D2D.
   if (gfxConfig::IsEnabled(Feature::D3D11_COMPOSITING)) {
diff --git a/gfx/webrender_bindings/RenderCompositorD3D11SWGL.cpp b/gfx/webrender_bindings/RenderCompositorD3D11SWGL.cpp
index 299625665445..3e338a461b83 100644
--- a/gfx/webrender_bindings/RenderCompositorD3D11SWGL.cpp
+++ b/gfx/webrender_bindings/RenderCompositorD3D11SWGL.cpp
@@ -379,6 +379,7 @@ RenderCompositorD3D11SWGL::CreateStagingTexture(const gfx::IntSize aSize) {
   MOZ_ASSERT(SUCCEEDED(hr));
   if (!cpuTexture) {
     gfxCriticalNote << "Failed to create StagingTexture: " << aSize;
+    RenderThread::Get()->HandleWebRenderError(WebRenderError::NEW_SURFACE);
   }
   return cpuTexture.forget();
 }
@@ -415,6 +416,7 @@ RenderCompositorD3D11SWGL::DoCreateTile(Surface* aSurface) {
   MOZ_ASSERT(SUCCEEDED(hr));
   if (!texture) {
     gfxCriticalNote << "Failed to allocate Texture2D: " << aSurface->TileSize();
+    RenderThread::Get()->HandleWebRenderError(WebRenderError::NEW_SURFACE);
     return MakeUnique<TileD3D11>(nullptr, nullptr, nullptr, aSurface, this);
   }
 
diff --git a/widget/nsBaseWidget.cpp b/widget/nsBaseWidget.cpp
index 8f19afdfbab5..8adfa1306010 100644
--- a/widget/nsBaseWidget.cpp
+++ b/widget/nsBaseWidget.cpp
@@ -1237,7 +1237,7 @@ already_AddRefed<LayerManager> nsBaseWidget::CreateCompositorSession(
 #ifdef XP_WIN
     if (supportsAcceleration) {
       options.SetAllowSoftwareWebRenderD3D11(
-          StaticPrefs::gfx_webrender_software_d3d11_AtStartup());
+          gfx::gfxVars::AllowSoftwareWebRenderD3D11());
     }
 #elif defined(MOZ_WIDGET_ANDROID)
     MOZ_ASSERT(supportsAcceleration);