[Mesa-dev] Mesa (master): egl: Native Display autodetection

Benjamin Franzke benjaminfranzke at googlemail.com
Mon Aug 15 01:20:57 PDT 2011


2011/8/15 Cooper Yuan <cooperyuan at gmail.com>:
> so, export EGL_PLATFORM=drm, is still working, right?

Yes, and has a higher priority than the autodetection.
>
> On Mon, Aug 15, 2011 at 3:47 PM, Benjamin Franzke
> <bnf at kemper.freedesktop.org> wrote:
>>
>> Module: Mesa
>> Branch: master
>> Commit: 85fe9484945cb57ffd49df248b0e5057eba6af04
>> URL:
>>  http://cgit.freedesktop.org/mesa/mesa/commit/?id=85fe9484945cb57ffd49df248b0e5057eba6af04
>>
>> Author: Benjamin Franzke <benjaminfranzke at googlemail.com>
>> Date:   Tue Aug  9 14:23:18 2011 +0200
>>
>> egl: Native Display autodetection
>>
>> EGL doesnt define howto manage different native platforms.
>> So mesa has a builtime configurable default platform,
>> whith non-standard envvar (EGL_PLATFORM) overwrites.
>> This caused unneeded bugreports, when EGL_PLATFORM was forgotten.
>>
>> Detection is grouped into basic types of NativeDisplays (which itself
>> needs to be detected).  The final decision is based on characteristcs
>> of these basic types:
>>
>>  File Desciptor based platforms (fbdev):
>>    - fstat(2) to check for being a fd that belongs to a character device
>>    - check kernel subsystem (todo)
>>
>>  Pointer to structuctures (x11, wayland, drm/gbm):
>>    - mincore(2) to check whether its valid pointer to some memory.
>>    - magic elements (e.g. pointers to exported symbols):
>>      o wayland display stores interface type pointer (first elm.)
>>      o gbm stores pointer to its constructor (first elm.)
>>      o x11 as a fallback (FIXME?)
>>
>> Reviewed-by: Kristian Høgsberg <krh at bitplanet.net>
>>
>> ---
>>
>>  configure.ac              |    2 +
>>  src/egl/main/Makefile     |   13 ++++++
>>  src/egl/main/eglapi.c     |    8 ++--
>>  src/egl/main/egldisplay.c |  100
>> +++++++++++++++++++++++++++++++++++++++++++-
>>  src/egl/main/egldisplay.h |    2 +-
>>  5 files changed, 117 insertions(+), 8 deletions(-)
>>
>> diff --git a/configure.ac b/configure.ac
>> index 1b1823a..9195da9 100644
>> --- a/configure.ac
>> +++ b/configure.ac
>> @@ -1370,6 +1370,8 @@ if test "x$enable_egl" = xyes; then
>>     EGL_LIB_DEPS="$DLOPEN_LIBS $SELINUX_LIBS -lpthread"
>>     EGL_DRIVERS_DIRS=""
>>
>> +    AC_CHECK_FUNC(mincore, [DEFINES="$DEFINES -DHAVE_MINCORE"])
>> +
>>     if test "$enable_static" != yes; then
>>         # build egl_glx when libGL is built
>>         if test "x$enable_glx" = xyes; then
>> diff --git a/src/egl/main/Makefile b/src/egl/main/Makefile
>> index 775fbbe..c100fbf 100644
>> --- a/src/egl/main/Makefile
>> +++ b/src/egl/main/Makefile
>> @@ -93,6 +93,19 @@ ifeq ($(firstword $(EGL_PLATFORMS)),fbdev)
>>  EGL_NATIVE_PLATFORM=_EGL_PLATFORM_FBDEV
>>  endif
>>
>> +ifneq ($(findstring x11, $(EGL_PLATFORMS)),)
>> +LOCAL_CFLAGS += -DHAVE_X11_PLATFORM
>> +endif
>> +ifneq ($(findstring wayland, $(EGL_PLATFORMS)),)
>> +LOCAL_CFLAGS += -DHAVE_WAYLAND_PLATFORM
>> +endif
>> +ifneq ($(findstring drm, $(EGL_PLATFORMS)),)
>> +LOCAL_CFLAGS += -DHAVE_DRM_PLATFORM
>> +endif
>> +ifneq ($(findstring fbdev, $(EGL_PLATFORMS)),)
>> +LOCAL_CFLAGS += -DHAVE_FBDEV_PLATFORM
>> +endif
>> +
>>  LOCAL_CFLAGS += \
>>        -D_EGL_NATIVE_PLATFORM=$(EGL_NATIVE_PLATFORM) \
>>        -D_EGL_DRIVER_SEARCH_DIR=\"$(EGL_DRIVER_INSTALL_DIR)\"
>> diff --git a/src/egl/main/eglapi.c b/src/egl/main/eglapi.c
>> index 0ba7794..5d186c6 100644
>> --- a/src/egl/main/eglapi.c
>> +++ b/src/egl/main/eglapi.c
>> @@ -301,7 +301,7 @@ _eglUnlockDisplay(_EGLDisplay *dpy)
>>  EGLDisplay EGLAPIENTRY
>>  eglGetDisplay(EGLNativeDisplayType nativeDisplay)
>>  {
>> -   _EGLPlatformType plat = _eglGetNativePlatform();
>> +   _EGLPlatformType plat = _eglGetNativePlatform(nativeDisplay);
>>    _EGLDisplay *dpy = _eglFindDisplay(plat, (void *) nativeDisplay);
>>    return _eglGetDisplayHandle(dpy);
>>  }
>> @@ -538,7 +538,7 @@ eglCreateWindowSurface(EGLDisplay dpy, EGLConfig
>> config,
>>    EGLSurface ret;
>>
>>    _EGL_CHECK_CONFIG(disp, conf, EGL_NO_SURFACE, drv);
>> -   if (disp->Platform != _eglGetNativePlatform())
>> +   if (disp->Platform != _eglGetNativePlatform(disp->PlatformDisplay))
>>       RETURN_EGL_ERROR(disp, EGL_BAD_NATIVE_WINDOW, EGL_NO_SURFACE);
>>
>>    surf = drv->API.CreateWindowSurface(drv, disp, conf, window,
>> attrib_list);
>> @@ -559,7 +559,7 @@ eglCreatePixmapSurface(EGLDisplay dpy, EGLConfig
>> config,
>>    EGLSurface ret;
>>
>>    _EGL_CHECK_CONFIG(disp, conf, EGL_NO_SURFACE, drv);
>> -   if (disp->Platform != _eglGetNativePlatform())
>> +   if (disp->Platform != _eglGetNativePlatform(disp->PlatformDisplay))
>>       RETURN_EGL_ERROR(disp, EGL_BAD_NATIVE_PIXMAP, EGL_NO_SURFACE);
>>
>>    surf = drv->API.CreatePixmapSurface(drv, disp, conf, pixmap,
>> attrib_list);
>> @@ -720,7 +720,7 @@ eglCopyBuffers(EGLDisplay dpy, EGLSurface surface,
>> EGLNativePixmapType target)
>>    EGLBoolean ret;
>>
>>    _EGL_CHECK_SURFACE(disp, surf, EGL_FALSE, drv);
>> -   if (disp->Platform != _eglGetNativePlatform())
>> +   if (disp->Platform != _eglGetNativePlatform(disp->PlatformDisplay))
>>       RETURN_EGL_ERROR(disp, EGL_BAD_NATIVE_PIXMAP, EGL_FALSE);
>>    ret = drv->API.CopyBuffers(drv, disp, surf, target);
>>
>> diff --git a/src/egl/main/egldisplay.c b/src/egl/main/egldisplay.c
>> index 60f3177..2849dd9 100644
>> --- a/src/egl/main/egldisplay.c
>> +++ b/src/egl/main/egldisplay.c
>> @@ -43,6 +43,23 @@
>>  #include "eglmutex.h"
>>  #include "egllog.h"
>>
>> +/* Includes for _eglNativePlatformDetectNativeDisplay */
>> +#ifdef HAVE_MINCORE
>> +#include <unistd.h>
>> +#include <sys/mman.h>
>> +#endif
>> +#ifdef HAVE_WAYLAND_PLATFORM
>> +#include <wayland-client.h>
>> +#endif
>> +#ifdef HAVE_DRM_PLATFORM
>> +#include <gbm.h>
>> +#endif
>> +#ifdef HAVE_FBDEV_PLATFORM
>> +#include <stdint.h>
>> +#include <sys/types.h>
>> +#include <sys/stat.h>
>> +#endif
>> +
>>
>>  /**
>>  * Return the native platform by parsing EGL_PLATFORM.
>> @@ -84,17 +101,94 @@ _eglGetNativePlatformFromEnv(void)
>>
>>
>>  /**
>> + * Perform validity checks on a generic pointer.
>> + */
>> +static EGLBoolean
>> +_eglPointerIsDereferencable(void *p)
>> +{
>> +#ifdef HAVE_MINCORE
>> +   uintptr_t addr = (uintptr_t) p;
>> +   unsigned char valid = 0;
>> +   const long page_size = getpagesize();
>> +
>> +   if (p == NULL)
>> +      return EGL_FALSE;
>> +
>> +   /* align addr to page_size */
>> +   addr &= ~(page_size - 1);
>> +
>> +   if (mincore((void *) addr, page_size, &valid) < 0) {
>> +      _eglLog(_EGL_DEBUG, "mincore failed: %m");
>> +      return EGL_FALSE;
>> +   }
>> +
>> +   return (valid & 0x01) == 0x01;
>> +#else
>> +   return p != NULL;
>> +#endif
>> +}
>> +
>> +
>> +/**
>> + * Try detecting native platform with the help of native display
>> characteristcs.
>> + */
>> +static _EGLPlatformType
>> +_eglNativePlatformDetectNativeDisplay(EGLNativeDisplayType nativeDisplay)
>> +{
>> +#ifdef HAVE_FBDEV_PLATFORM
>> +   struct stat buf;
>> +#endif
>> +
>> +   if (nativeDisplay == EGL_DEFAULT_DISPLAY)
>> +      return _EGL_INVALID_PLATFORM;
>> +
>> +#ifdef HAVE_FBDEV_PLATFORM
>> +   /* fbdev is the only platform that can be a file descriptor. */
>> +   if (fstat((intptr_t) nativeDisplay, &buf) == 0 &&
>> S_ISCHR(buf.st_mode))
>> +      return _EGL_PLATFORM_FBDEV;
>> +#endif
>> +
>> +   if (_eglPointerIsDereferencable(nativeDisplay)) {
>> +      void *first_pointer = *(void **) nativeDisplay;
>> +
>> +#ifdef HAVE_WAYLAND_PLATFORM
>> +      /* wl_display is a wl_proxy, which is a wl_object.
>> +       * wl_object's first element points to the interfacetype. */
>> +      if (first_pointer == &wl_display_interface)
>> +         return _EGL_PLATFORM_WAYLAND;
>> +#endif
>> +
>> +#ifdef HAVE_DRM_PLATFORM
>> +      /* gbm has a pointer to its constructor as first element. */
>> +      if (first_pointer == gbm_create_device)
>> +         return _EGL_PLATFORM_DRM;
>> +#endif
>> +
>> +#ifdef HAVE_X11_PLATFORM
>> +      /* If not matched to any other platform, fallback to x11. */
>> +      return _EGL_PLATFORM_X11;
>> +#endif
>> +   }
>> +
>> +   return _EGL_INVALID_PLATFORM;
>> +}
>> +
>> +
>> +/**
>>  * Return the native platform.  It is the platform of the EGL native
>> types.
>>  */
>>  _EGLPlatformType
>> -_eglGetNativePlatform(void)
>> +_eglGetNativePlatform(EGLNativeDisplayType nativeDisplay)
>>  {
>>    static _EGLPlatformType native_platform = _EGL_INVALID_PLATFORM;
>>
>>    if (native_platform == _EGL_INVALID_PLATFORM) {
>>       native_platform = _eglGetNativePlatformFromEnv();
>> -      if (native_platform == _EGL_INVALID_PLATFORM)
>> -         native_platform = _EGL_NATIVE_PLATFORM;
>> +      if (native_platform == _EGL_INVALID_PLATFORM) {
>> +         native_platform =
>> _eglNativePlatformDetectNativeDisplay(nativeDisplay);
>> +         if (native_platform == _EGL_INVALID_PLATFORM)
>> +            native_platform = _EGL_NATIVE_PLATFORM;
>> +      }
>>    }
>>
>>    return native_platform;
>> diff --git a/src/egl/main/egldisplay.h b/src/egl/main/egldisplay.h
>> index 9cd4dbf..05335ad 100644
>> --- a/src/egl/main/egldisplay.h
>> +++ b/src/egl/main/egldisplay.h
>> @@ -150,7 +150,7 @@ struct _egl_display
>>
>>
>>  extern _EGLPlatformType
>> -_eglGetNativePlatform(void);
>> +_eglGetNativePlatform(EGLNativeDisplayType nativeDisplay);
>>
>>
>>  extern void
>>
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>
>
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