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-rw-r--r--wiki/Graphics-Execution.md46
1 files changed, 28 insertions, 18 deletions
diff --git a/wiki/Graphics-Execution.md b/wiki/Graphics-Execution.md
index cba9732..ffbcfaf 100644
--- a/wiki/Graphics-Execution.md
+++ b/wiki/Graphics-Execution.md
@@ -12,7 +12,7 @@
> [`../docs/04-implementation/04-real-render-walls.md`](../docs/04-implementation/04-real-render-walls.md)
> (the measured walls); the docs tree wins on disagreement.
-Status: 2026-11-09, tree `master @ e342bd0f`. Tags: `[live]` observed end to
+Status: 2026-11-09, tree `master @ 21e0d611`. Tags: `[live]` observed end to
end; `[wip]` partially built; `[wall]` current blocker; `[target]` defined
success state; `[planned]` designed, not built.
@@ -89,10 +89,10 @@ fidelity:
kick channel (`0xbfef0002`) is decoded from its ring head with its
class-2D notification authored. The X DDX waits are fixed (class-aware
display arm, `0x8000 -> 0` notification completion, decoded GL release
- applied), and GZDoom reached `MAP01` once the DDX push-buffer loop was
- unblocked. What remains is the renderer backend path (NVIDIA Vulkan ICD or
- forced GLX), the DDX get-word/notifier completion, and physical dispatch
- of the client's draws (§6).
+ applied), and with GLX forced (`SDL_VIDEO_X11_FORCE_EGL=0`) the windowed
+ GL path selects `libnvidia-glcore`. What remains is the kernel-visible GL
+ present/kick completion, the DDX get-word/notifier recycle, and physical
+ dispatch of the client's draws (§6).
## 4. The channel and object picture
@@ -139,7 +139,10 @@ until it posts, so the X server's mode set finishes. For the X DDX's own 2D
push buffers, completion also requires the GPU-written engine get word to
advance and the notifier to be recycled to `0xffff` after a kick; both are
host-side levers now, and a diagnostic write of the get word released the
-DDX's reserve loop.
+DDX's reserve loop. For a windowed GL client the present is a kick whose
+completion the guest kernel observes by polling its per-slot
+`/dev/nvidia-modeset` fd; the host must complete the exact notifier page the
+kernel watches and signal that event, not only write the notifier memory.
During bring-up the module also carries a **diagnostics-only mirror** for apps
that spin on a shared progress word; it exists so a run can proceed while the
@@ -148,11 +151,14 @@ requires it switched off, along with any external poke.
## 6. Where the frontier is (ranked walls)
-1. **The renderer backend path** `[wall]`. GZDoom's default Vulkan backend
- fails at `vkCreateDevice` in the NVIDIA Vulkan ICD, and the default
- OpenGL/EGL path falls back to Mesa (`llvmpipe`). The campaign is forcing
- GLX (`SDL_VIDEO_X11_FORCE_EGL=0`) so the client uses the NVIDIA GL stack;
- the first NVIDIA-path frame is gated here.
+1. **Kernel-visible GL present completion** `[wall]`. With GLX forced the
+ windowed client uses `libnvidia-glcore`; the minimal `glxgears` then hangs
+ in the glcore kick wait: the client polls its per-slot
+ `/dev/nvidia-modeset` fd (`poll(POLLIN, 1 s)`). The host's sweep completes
+ the beef notifier memory, but the guest kernel never signals the event the
+ poll waits on. The exact notifier page the kernel watches must be
+ completed and the guest event signalled (the kick-notify executor), not
+ just the memory written.
2. **The X DDX push-buffer completion** `[wall]`. The DDX's 2D reserve loop
exits only when the GPU-written engine get word advances (`get <= put`) and
the kick requires the notifier to be recycled to `0xffff` after
@@ -168,9 +174,9 @@ requires it switched off, along with any external poke.
dispatch to the physical GR engine (`forwarded=0`); the draws are decoded
and host-completed, not executed on hardware.
5. **Non-black frames and sustained rate** `[wall]`/`[target]`. Once the
- NVIDIA renderer path and the DDX get-word/notifier completion land, the
- capture must show motion, then 60 fps in one VM with no forcing, then two
- VMs on two mediated devices with non-black frames in both.
+ kernel-visible present completion and the DDX get-word/notifier completion
+ land, the capture must show motion, then 60 fps in one VM with no forcing,
+ then two VMs on two mediated devices with non-black frames in both.
## 7. What is proven today
@@ -182,6 +188,8 @@ requires it switched off, along with any external poke.
| `glxinfo` reports the emulated GPU with the NVIDIA renderer (OpenGL 4.6.0, direct rendering) | `[live]` |
| GZDoom obtains a real GL context; windowed reaches renderer startup | `[live]` (pixels frontier) |
| GZDoom reaches `MAP01` on Mesa llvmpipe (not the emulated vGPU path) | `[wip]` |
+| Forced GLX (`SDL_VIDEO_X11_FORCE_EGL=0`) selects `libnvidia-glcore` | `[live]` |
+| Windowed GL present/kick completion (minimal `glxgears`) | `[wall]` |
| X server survives the GZDoom run on a 12 GB guest (the DDX's 4 GB sysmem allocation forces the size) | `[live]` |
| GL section capture: the X server's `0xC597` stream decoded | `[live]` |
| Verbatim 3D method-stream replay retired by the engine (no MMU fault) | `[live]` |
@@ -189,7 +197,8 @@ requires it switched off, along with any external poke.
| 2D screen fills and copy-engine present ops execute | `[live]` |
| Direct GL client: device-init gate handled, channels allocate, readback path returns clean | `[live]` |
| Direct GL client channels submit and retire (GR `0xbeef0100`, CE `0xbeef0101`/`0xbeef0102`); DDX kick channel decoded | `[live]` |
-| NVIDIA Vulkan ICD creates a device, or forced GLX reaches glcore | `[wall]` |
+| Guest kernel observes the kick completion and signals the modeset event | `[wall]` |
+| NVIDIA Vulkan ICD creates a device | `[wall]` |
| DDX push-buffer get-word publish and notifier recycle | `[wall]` |
| Physical dispatch of the direct-GL draws (`forwarded=0`) | `[wall]` |
| Non-black pixels from the emulated vGPU's 3D pipeline | `[wall]` |
@@ -200,9 +209,10 @@ requires it switched off, along with any external poke.
* No non-black pixel has been produced by the emulated vGPU's 3D pipeline yet.
* Display/KMS bring-up (NvKms, `/dev/dri`, X, a real GL context) is not a
rendered-frame claim; GZDoom reaching `MAP01` on Mesa llvmpipe is not the
- emulated-vGPU path either. The NVIDIA renderer path, the DDX
- get-word/notifier completion and the physical dispatch of the GL draws are
- the current walls.
+ emulated-vGPU path, and the later forced-GLX run selects `libnvidia-glcore`
+ but hangs in the present/kick wait. The kernel-visible present completion,
+ the DDX get-word/notifier completion and the physical dispatch of the GL
+ draws are the current walls.
* No frame-rate or latency numbers: the scheduled measurement is defined
(60 fps over 60 s, no forcing) but not yet met.
* The `virgl`-based demo videos are a different, labelled path — not this one.