From 286e4af5825b4f4c2c5a15950c3e926a7aa7417b Mon Sep 17 00:00:00 2001 From: Swung0x48 Date: Fri, 9 Oct 2026 14:23:56 -0400 Subject: [PATCH] Docs: MobileGL no longer steps aside for LIBGL_ALWAYS_SOFTWARE. --- .claude/skills/anland-mobilegl-plasma/SKILL.md | 2 +- MobileGL/Init.h | 7 ++++--- docs/Disaggregated/notes/anland/runbook-plasma.md | 2 +- 3 files changed, 6 insertions(+), 5 deletions(-) diff --git a/.claude/skills/anland-mobilegl-plasma/SKILL.md b/.claude/skills/anland-mobilegl-plasma/SKILL.md index 47ea37dc..f35dbcaa 100644 --- a/.claude/skills/anland-mobilegl-plasma/SKILL.md +++ b/.claude/skills/anland-mobilegl-plasma/SKILL.md @@ -108,7 +108,7 @@ Installed by `xdeploy.sh` (and anland's `anland-build-client.sh`), so any proces Precedence is environment > `/etc/mobilegl/backend` (backend only) > client.conf > built-in; `MOBILEGL_CONFIG_FILE` / `MOBILEGL_BACKEND_FILE` name other files (empty = off); a server process never reads them. -**Fallback.** Before bringing anything up the client probes the configured endpoint (one non-blocking connect, `MOBILEGL_IPC_PROBE_TIMEOUT_MS`, default 250, 0 = off; a refused abstract socket answers in ~0.2 ms). With no server: the EGL vendor returns `EGL_NO_DISPLAY` and no devices (glvnd moves on to the other vendor), the GLX vendor fails `__glx_Main` (libGLX falls back to the vendor Xwayland names), and `mobilegl_gbm` fails `create_device` (libgbm falls back to the device's own backend). Client queries (`eglQueryString(EGL_NO_DISPLAY)`, `eglGetProcAddress`) never bring a session up. MobileGL also steps aside for a GBM device another backend created and for `LIBGL_ALWAYS_SOFTWARE=1` - that is how a software Xwayland (`ANLAND_XWAYLAND_GLAMOR=0`, KWin's patch sets it then) keeps the software stack. MobileGL never opens an X connection to a display its own process serves (`MG_Util/X11/DisplayGuard.h`; `MOBILEGL_X11_DIAL=0` forbids all), which is what made a glamor Xwayland deadlock on itself before. Show it without stopping the real server: +**Fallback.** Before bringing anything up the client probes the configured endpoint (one non-blocking connect, `MOBILEGL_IPC_PROBE_TIMEOUT_MS`, default 250, 0 = off; a refused abstract socket answers in ~0.2 ms). With no server: the EGL vendor returns `EGL_NO_DISPLAY` and no devices (glvnd moves on to the other vendor), the GLX vendor fails `__glx_Main` (libGLX falls back to the vendor Xwayland names), and `mobilegl_gbm` fails `create_device` (libgbm falls back to the device's own backend). Client queries (`eglQueryString(EGL_NO_DISPLAY)`, `eglGetProcAddress`) never bring a session up. MobileGL also steps aside for a GBM device another backend created. It no longer steps aside for `LIBGL_ALWAYS_SOFTWARE=1` (918d40dd): that is Mesa's software-renderer selection, not a reason to disable MobileGL's entry points, so a process that sets it (a software Xwayland included) is still served by MobileGL while a server answers. MobileGL never opens an X connection to a display its own process serves (`MG_Util/X11/DisplayGuard.h`; `MOBILEGL_X11_DIAL=0` forbids all), which is what made a glamor Xwayland deadlock on itself before. Show it without stopping the real server: ```sh sed 's|^MOBILEGL_IPC_CONTROL=.*|MOBILEGL_IPC_CONTROL=unix:@nobody|' /etc/mobilegl/client.conf > /tmp/down.conf sudo -u swung0x48 env -i HOME=/home/swung0x48 PATH=/usr/bin XDG_RUNTIME_DIR=/run/user/1000 WAYLAND_DISPLAY=wayland-0 \ diff --git a/MobileGL/Init.h b/MobileGL/Init.h index 5b41d9cc..78468e25 100644 --- a/MobileGL/Init.h +++ b/MobileGL/Init.h @@ -33,10 +33,11 @@ namespace MobileGL { } // namespace MG_ConfigLoader // Whether this process can be served right now. False when MobileGL is configured to reach a - // server that is not there (or a split session already failed to come up), or when the process - // asked for software rendering (LIBGL_ALWAYS_SOFTWARE, desktop Linux), so a + // server that is not there (or a split session already failed to come up), so a // caller that can choose another implementation - the system's EGL/GLX/GBM loaders - should - // decline rather than hand out something that cannot draw. Cheap: once true it stays true + // decline rather than hand out something that cannot draw. LIBGL_ALWAYS_SOFTWARE does NOT + // make it false: that variable selects the system GL's software renderer and is not a reason + // to disable MobileGL's entry points. Cheap: once true it stays true // until the library is torn down, and a probe is one non-blocking connect with a short bound. Bool ImplementationAvailable(); diff --git a/docs/Disaggregated/notes/anland/runbook-plasma.md b/docs/Disaggregated/notes/anland/runbook-plasma.md index b990b7cf..4d523985 100644 --- a/docs/Disaggregated/notes/anland/runbook-plasma.md +++ b/docs/Disaggregated/notes/anland/runbook-plasma.md @@ -105,7 +105,7 @@ MSYS2_ARG_CONV_EXCL='*' wsl -d archlinux -- bash -lc 'cd ~/mgl-anl-bld && ctest 优先级：环境变量 > `/etc/mobilegl/backend`（只管后端）> client.conf > 内置默认；`MOBILEGL_CONFIG_FILE` / `MOBILEGL_BACKEND_FILE` 可指向别的文件（设为空即关闭）；server 进程不读这些文件。 -**回退**：真正拉起之前 client 先探一次配置的 endpoint（一次非阻塞 connect，`MOBILEGL_IPC_PROBE_TIMEOUT_MS` 默认 250，0 关闭；被拒的抽象 socket 约 0.2 ms 就有结果）。没有 server 时：EGL vendor 返回 `EGL_NO_DISPLAY`、设备数 0（glvnd 换下一个 vendor），GLX vendor 的 `__glx_Main` 失败（libGLX 回退到 Xwayland 报的 vendor），`mobilegl_gbm` 的 `create_device` 失败（libgbm 回退到设备自己的后端）。客户端查询（`eglQueryString(EGL_NO_DISPLAY)`、`eglGetProcAddress`）从不拉起会话。对别的后端创建的 GBM 设备和 `LIBGL_ALWAYS_SOFTWARE=1` 的进程，MobileGL 同样让开——Xwayland（KWin 补丁给它设了这个）因此继续走软件栈。不停真 server 的演示： +**回退**：真正拉起之前 client 先探一次配置的 endpoint（一次非阻塞 connect，`MOBILEGL_IPC_PROBE_TIMEOUT_MS` 默认 250，0 关闭；被拒的抽象 socket 约 0.2 ms 就有结果）。没有 server 时：EGL vendor 返回 `EGL_NO_DISPLAY`、设备数 0（glvnd 换下一个 vendor），GLX vendor 的 `__glx_Main` 失败（libGLX 回退到 Xwayland 报的 vendor），`mobilegl_gbm` 的 `create_device` 失败（libgbm 回退到设备自己的后端）。客户端查询（`eglQueryString(EGL_NO_DISPLAY)`、`eglGetProcAddress`）从不拉起会话。对别的后端创建的 GBM 设备，MobileGL 同样让开。`LIBGL_ALWAYS_SOFTWARE=1` 不再让它让开（918d40dd）：那只是 Mesa 的软件渲染器选择，不是关掉 MobileGL 入口的理由；只要有 server，带这个变量的进程（包括被 KWin 补丁设了它的 Xwayland）照样由 MobileGL 服务。不停真 server 的演示： ```sh sed 's|^MOBILEGL_IPC_CONTROL=.*|MOBILEGL_IPC_CONTROL=unix:@nobody|' /etc/mobilegl/client.conf > /tmp/down.conf sudo -u swung0x48 env -i HOME=/home/swung0x48 PATH=/usr/bin XDG_RUNTIME_DIR=/run/user/1000 WAYLAND_DISPLAY=wayland-0 \