From 6d791a262fefd8336e403160af3e2e273a617358 Mon Sep 17 00:00:00 2001
From: Elie Habib <elie.habib@gmail.com>
Date: Thu, 26 Feb 2026 23:23:07 +0400
Subject: [PATCH] fix(linux): disable WebKitGTK compositing in VMs to fix black
 iframes
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WebKitGTK promotes iframes, <video>, and canvas elements to GPU-textured
compositing layers. In VMs (Apple Virtualization.framework, QEMU, VMware,
etc.) the virtio-gpu driver often only supports 2D or limited GL, so GBM
buffer allocation for compositing layers fails silently — rendering
iframe/video content as black while the main page works fine.

Detect VM environments via /proc/cpuinfo hypervisor flag and sys_vendor
strings, then set WEBKIT_DISABLE_COMPOSITING_MODE=1 and
LIBGL_ALWAYS_SOFTWARE=1 to force software rendering for all content.
Native Linux machines with real GPUs are unaffected.
---
 src-tauri/src/main.rs | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/src-tauri/src/main.rs b/src-tauri/src/main.rs
index 15b804ba9..001384406 100644
--- a/src-tauri/src/main.rs
+++ b/src-tauri/src/main.rs
@@ -1131,6 +1131,38 @@ fn main() {
             unsafe { env::set_var("WEBKIT_DISABLE_DMABUF_RENDERER", "1") };
         }
 
+        // WebKitGTK promotes iframes, <video>, and canvas to GPU-textured
+        // compositing layers.  In VMs (Apple Virtualization.framework,
+        // QEMU/KVM, VMware, etc.) the virtio-gpu driver often only supports
+        // 2D or limited GL — GBM buffer allocation for compositing layers
+        // fails silently, rendering iframe/video content as black while the
+        // main page (software-tiled) works fine.
+        //
+        // Detect VM environments via /proc/cpuinfo "hypervisor" flag or
+        // sys_vendor strings and disable accelerated compositing + force
+        // software GL so all content renders through the CPU path.
+        let in_vm = std::fs::read_to_string("/proc/cpuinfo")
+            .map(|c| c.contains("hypervisor"))
+            .unwrap_or(false)
+            || std::fs::read_to_string("/sys/class/dmi/id/sys_vendor")
+                .map(|v| {
+                    let v = v.trim().to_lowercase();
+                    v.contains("qemu") || v.contains("vmware") || v.contains("virtualbox")
+                        || v.contains("apple") || v.contains("parallels") || v.contains("xen")
+                        || v.contains("microsoft") || v.contains("innotek")
+                })
+                .unwrap_or(false);
+
+        if in_vm {
+            if env::var_os("WEBKIT_DISABLE_COMPOSITING_MODE").is_none() {
+                unsafe { env::set_var("WEBKIT_DISABLE_COMPOSITING_MODE", "1") };
+            }
+            if env::var_os("LIBGL_ALWAYS_SOFTWARE").is_none() {
+                unsafe { env::set_var("LIBGL_ALWAYS_SOFTWARE", "1") };
+            }
+            eprintln!("[tauri] VM detected; disabled WebKitGTK accelerated compositing for iframe/video compatibility");
+        }
+
         // On Wayland-only compositors (e.g. niri, river, sway without XWayland),
         // GTK3 may fail to initialise if it defaults to X11 backend first and no
         // DISPLAY is set.  Explicitly prefer the Wayland backend when a Wayland