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Imagine there are 2 threads that both call _eglGetNativePlatform() simultaneously: - thread 1 completes the first "if (native_platform == _EGL_INVALID_PLATFORM)" check and is preempted to do something else - thread 2 executes the whole function, does "native_platform = _EGL_NATIVE_PLATFORM" and just before returning it's preempted - thread 1 wakes up and calls _eglGetNativePlatformFromEnv() which returns _EGL_INVALID_PLATFORM because no env vars are set, updates native_platform and then gets preempted again - thread 2 wakes up and returns wrong _EGL_INVALID_PLATFORM Solve this by doing the detection in a local var and only overwriting the global one at the end, if no other thread has updated it since. This means the platform detected in the thread might not be the platform returned by the function, but this is a different issue that will need to be discussed when this becomes possible. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=101252 Signed-off-by: Eric Engestrom <eric@engestrom.ch> Reviewed-by: Grazvydas Ignotas <notasas@gmail.com> Acked-by: Emil Velikov <emil.l.velikov@gmail.com> |
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| .. | ||
| 50_mesa.json | ||
| egl.def | ||
| egl.pc.in | ||
| eglapi.c | ||
| eglapi.h | ||
| eglarray.c | ||
| eglarray.h | ||
| eglconfig.c | ||
| eglconfig.h | ||
| eglcontext.c | ||
| eglcontext.h | ||
| eglcurrent.c | ||
| eglcurrent.h | ||
| egldefines.h | ||
| egldispatchstubs.c | ||
| egldispatchstubs.h | ||
| egldisplay.c | ||
| egldisplay.h | ||
| egldriver.c | ||
| egldriver.h | ||
| eglentrypoint.h | ||
| eglfallbacks.c | ||
| eglglobals.c | ||
| eglglobals.h | ||
| eglglvnd.c | ||
| eglimage.c | ||
| eglimage.h | ||
| egllog.c | ||
| egllog.h | ||
| eglsurface.c | ||
| eglsurface.h | ||
| eglsync.c | ||
| eglsync.h | ||
| egltypedefs.h | ||
| README.txt | ||
Notes about the EGL library: The EGL code here basically consists of two things: 1. An EGL API dispatcher. This directly routes all the eglFooBar() API calls into driver-specific functions. 2. Fallbacks for EGL API functions. A driver _could_ implement all the EGL API calls from scratch. But in many cases, the fallbacks provided in libEGL (such as eglChooseConfig()) will do the job. Bootstrapping: When the apps calls eglInitialize() a device driver is selected and loaded (look for _eglAddDrivers() and _eglLoadModule() in egldriver.c). The built-in driver's entry point function is then called. This driver function allocates, initializes and returns a new _EGLDriver object (usually a subclass of that type). As part of initialization, the dispatch table in _EGLDriver->API must be populated with all the EGL entrypoints. Typically, _eglInitDriverFallbacks() can be used to plug in default/fallback functions. Some functions like driver->API.Initialize and driver->API.Terminate _must_ be implemented with driver-specific code (no default/fallback function is possible). Shortly after, the driver->API.Initialize() function is executed. Any additional driver initialization that wasn't done in the driver entry point should be done at this point. Typically, this will involve setting up visual configs, etc. Special Functions: Certain EGL functions _must_ be implemented by the driver. This includes: eglCreateContext eglCreateWindowSurface eglCreatePixmapSurface eglCreatePBufferSurface eglMakeCurrent eglSwapBuffers Most of the EGLConfig-related functions can be implemented with the defaults/fallbacks. Same thing for the eglGet/Query functions. Teardown: When eglTerminate() is called, the driver->API.Terminate() function is called. The driver should clean up after itself. eglTerminate() will then close/unload the driver (shared library). Subclassing: The internal libEGL data structures such as _EGLDisplay, _EGLContext, _EGLSurface, etc should be considered base classes from which drivers will derive subclasses.