diff -up firefox-85.0/widget/GfxInfoX11.cpp.firefox-kde-webrender firefox-85.0/widget/GfxInfoX11.cpp
--- firefox-85.0/widget/GfxInfoX11.cpp.firefox-kde-webrender	2021-02-01 16:15:09.807773987 +0100
+++ firefox-85.0/widget/GfxInfoX11.cpp	2021-02-01 16:20:26.115125315 +0100
@@ -713,6 +713,14 @@ const nsTArray<GfxDriverInfo>& GfxInfo::
         DRIVER_GREATER_THAN_OR_EQUAL, V(18, 0, 0, 0),
         "FEATURE_ROLLOUT_INTEL_GNOME_WAYLAND_MESA", "Mesa 18.0.0.0");
 
+    APPEND_TO_DRIVER_BLOCKLIST_EXT(
+        OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
+        DesktopEnvironment::KDE, WindowProtocol::Wayland,
+        DriverVendor::MesaAll, DeviceFamily::IntelRolloutWebRender,
+        nsIGfxInfo::FEATURE_WEBRENDER, nsIGfxInfo::FEATURE_ALLOW_ALWAYS,
+        DRIVER_GREATER_THAN_OR_EQUAL, V(18, 0, 0, 0),
+        "FEATURE_ROLLOUT_INTEL_GNOME_WAYLAND_MESA", "Mesa 18.0.0.0");
+
     // ATI Mesa baseline, chosen arbitrarily.
     APPEND_TO_DRIVER_BLOCKLIST_EXT(
         OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
@@ -727,6 +735,14 @@ const nsTArray<GfxDriverInfo>& GfxInfo::
         DriverVendor::MesaAll, DeviceFamily::AtiRolloutWebRender,
         nsIGfxInfo::FEATURE_WEBRENDER, nsIGfxInfo::FEATURE_ALLOW_ALWAYS,
         DRIVER_GREATER_THAN_OR_EQUAL, V(18, 0, 0, 0),
+        "FEATURE_ROLLOUT_ATI_GNOME_WAYLAND_MESA", "Mesa 18.0.0.0");
+
+    APPEND_TO_DRIVER_BLOCKLIST_EXT(
+        OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
+        DesktopEnvironment::KDE, WindowProtocol::Wayland,
+        DriverVendor::MesaAll, DeviceFamily::AtiRolloutWebRender,
+        nsIGfxInfo::FEATURE_WEBRENDER, nsIGfxInfo::FEATURE_ALLOW_ALWAYS,
+        DRIVER_GREATER_THAN_OR_EQUAL, V(18, 0, 0, 0),
         "FEATURE_ROLLOUT_ATI_GNOME_WAYLAND_MESA", "Mesa 18.0.0.0");
 
 #ifdef EARLY_BETA_OR_EARLIER