Allocate League's Metal drawables in VRAM

League sets framebufferOnly=NO on its CAMetalLayer, and QuartzCore read
that as needing host-visible coherent memory, so the game's final
render target and the linear image handed to OpenGL both lived in
system RAM (type 2 on the RX 6600) and crossed PCIe every frame.
framebufferOnly=NO only lets Metal sample or blit the texture: nothing
maps either image (replaceRegion aborts, getBytes is a stub, Indium
maps only Shared/Managed buffers).

Drawables now take the first allowed DEVICE_LOCAL type whatever
framebufferOnly says; the guest file /tmp/metal-no-drawable-vram
restores the old placement. metal-device.log shows drawable-vram=on and
storage=vram.

A native EGL/RADV test exported the drawable's linear image from VRAM
and imported it into GL with no errors and identical pixels. In a
practice-tool baron fight on the RX 6600 with the same champion it ran
about 20 FPS faster and the same when idle; not yet measured in an ARAM.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

docs/SETUP.md

@@ -101,6 +101,7 @@ Indium also contains experimental hand-off changes. They are **off by default**:
 | `/tmp/metal-skip-cpu-devices` | software Vulkan devices (lavapipe) are skipped while a hardware device exists |
 | `/tmp/metal-gpu` | diagnostic: selects the Vulkan device used for Metal by index or case-insensitive name substring instead of the loader's first device. The OpenGL context that presents does not follow it; see [hybrid laptops](TROUBLESHOOTING.md#hybrid-graphics-laptops-amdintel-igpu--nvidia). `METAL_INDIUM_GPU` is the environment equivalent; the file wins |
 | `/tmp/metal-all-devices` | a `VkDevice` is created for every supported Vulkan device, as before 2026-10-16. Without it only the selected device gets one; on a machine with lavapipe installed this also drops lavapipe's idle rasterizer threads |
+| `/tmp/metal-no-drawable-vram` | drawables of a layer with `framebufferOnly` off (League sets it off) go back to host-visible system RAM, as before 2026-10-16. Without the file they are allocated in GPU memory like `framebufferOnly` drawables; nothing maps drawable memory from the CPU. On the RX 6600 this gave about 20 FPS more in a practice-tool fight and the same FPS when idle, not yet measured in an ARAM. `/tmp/metal-device.log` shows `drawable-vram=on` and `storage=vram` |
 | `/tmp/metal-debug-waits` | diagnostic: counts how often and how long threads block at the hand-off waits and in `nextDrawable`, every 5 s in `/tmp/metal-trace.log`; the first check writes a `waits enabled` line |
 
 Create these files from inside the guest, for example `darling shell touch /tmp/metal-debug-waits`, or while Darling is shut down. The guest `/tmp` is `~/.darling/private/tmp` seen through Darling's overlay mount. A file created on the host in that directory while Darling runs may stay invisible to guest processes that already looked for it. The same applies to removing a file. The older `/tmp/metal-no-present-dispatch-wait`, `/tmp/metal-no-deferred-blit` and `/tmp/metal-no-skip-cpu-devices` files are ignored.

docs/TROUBLESHOOTING.md

@@ -193,7 +193,7 @@ The log also lists the selected device's memory heaps and types, and one line th
 [MetalDevice] pid=… memory alloc kind=texture storage=private typeBits=0x… type=1 flags=0x1(DEVICE_LOCAL) heap=0 heapDeviceLocal=yes firstFit=0 flags=0x0(none) heap=1 heapDeviceLocal=no changed=yes
 ```
 
-Resources only the GPU uses (`private`, `memoryless`, and `framebufferOnly` drawables) take the first allowed `DEVICE_LOCAL` type. Before 2026-10-16 they took the first allowed type (`firstFit`), which on NVIDIA can be system RAM; `changed=yes` marks where the two differ. `shared` and `managed` resources keep the first host-visible type. On the RX 6600 (RADV) type 0 is `DEVICE_LOCAL`, so nothing changes there.
+Resources only the GPU uses (`private`, `memoryless`, and drawables, including League's `framebufferOnly`-off ones unless `/tmp/metal-no-drawable-vram` exists) take the first allowed `DEVICE_LOCAL` type. Before 2026-10-16 they took the first allowed type (`firstFit`), which on NVIDIA can be system RAM; `changed=yes` marks where the two differ. `shared` and `managed` resources keep the first host-visible type. On the RX 6600 (RADV) type 0 is `DEVICE_LOCAL`, so nothing changes there.
 
 The first import of a drawable into the presenting OpenGL context, and the first semaphore import, are logged too; later ones only when they fail (at most five):