vo_opengl: mali fbdev support

Minimal support just for testing.

Only the window surface creation (including size determination) is
really platform specific, so this could be some generic thing with
platform-specific support as some sort of sub-driver, but on the other
hand I don't see much of a need for such a thing.

While most of the fbdev usage is done by the EGL driver, using this
fbdev ioctl is apparently the only way to get the display resolution.

DOCS/man/options.rst

@@ -4225,6 +4225,8 @@ The following video options are currently all specific to ``--vo=opengl`` and
         DRM/EGL
     x11egl
         X11/EGL
+    mali-fbdev
+        Direct fbdev/EGL support on some ARM/MALI devices.
 
 ``--opengl-es=<mode>``
     Select whether to use GLES:

video/out/opengl/context.c

@@ -45,6 +45,7 @@ extern const struct mpgl_driver mpgl_driver_angle;
 extern const struct mpgl_driver mpgl_driver_angle_es2;
 extern const struct mpgl_driver mpgl_driver_dxinterop;
 extern const struct mpgl_driver mpgl_driver_rpi;
+extern const struct mpgl_driver mpgl_driver_mali;
 
 static const struct mpgl_driver *const backends[] = {
 #if HAVE_RPI
@@ -78,6 +79,9 @@ static const struct mpgl_driver *const backends[] = {
 #if HAVE_EGL_DRM
     &mpgl_driver_drm_egl,
 #endif
+#if HAVE_MALI_FBDEV
+    &mpgl_driver_mali,
+#endif
 };
 
 // 0-terminated list of desktop GL versions a backend should try to

video/out/opengl/context_mali_fbdev.c

@@ -0,0 +1,167 @@
+/*
+ * This file is part of mpv.
+ *
+ * mpv is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * mpv is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with mpv.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stddef.h>
+#include <assert.h>
+#include <unistd.h>
+#include <dlfcn.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/ioctl.h>
+
+#include <linux/fb.h>
+#include <EGL/fbdev_window.h>
+
+#include "common/common.h"
+#include "context.h"
+#include "egl_helpers.h"
+
+static bool get_fbdev_size(int *w, int *h)
+{
+    int fd = open("/dev/fb0", O_RDWR | O_CLOEXEC);
+    if (fd < 0)
+        return false;
+
+    struct fb_var_screeninfo info = {0};
+    bool ok = !ioctl(fd, FBIOGET_VSCREENINFO, &info);
+    if (ok) {
+        *w = info.xres;
+        *h = info.yres;
+    }
+
+    close(fd);
+
+    return ok;
+}
+
+static void *get_proc_address(const GLubyte *name)
+{
+    void *p = eglGetProcAddress(name);
+    // EGL 1.4 (supported by the MALI drivers) does not necessarily return
+    // function pointers for core functions.
+    if (!p)
+        p = dlsym(RTLD_DEFAULT, name);
+    return p;
+}
+
+struct priv {
+    struct mp_log *log;
+    struct GL *gl;
+    EGLDisplay egl_display;
+    EGLConfig egl_config;
+    EGLContext egl_context;
+    EGLSurface egl_surface;
+    struct fbdev_window egl_window;
+    int w, h;
+};
+
+static void mali_uninit(struct MPGLContext *ctx)
+{
+    struct priv *p = ctx->priv;
+
+    if (p->egl_surface) {
+        eglMakeCurrent(p->egl_display, EGL_NO_SURFACE, EGL_NO_SURFACE,
+                       EGL_NO_CONTEXT);
+        eglDestroySurface(p->egl_display, p->egl_surface);
+    }
+    if (p->egl_context)
+        eglDestroyContext(p->egl_display, p->egl_context);
+    eglReleaseThread();
+}
+
+static int mali_init(struct MPGLContext *ctx, int flags)
+{
+    struct priv *p = ctx->priv;
+    p->log = ctx->vo->log;
+
+    if (!get_fbdev_size(&p->w, &p->h)) {
+        MP_FATAL(p, "Could not get fbdev size.\n");
+        goto fail;
+    }
+
+    p->egl_display = eglGetDisplay(EGL_DEFAULT_DISPLAY);
+    if (!eglInitialize(p->egl_display, NULL, NULL)) {
+        MP_FATAL(p, "EGL failed to initialize.\n");
+        goto fail;
+    }
+
+    EGLConfig config;
+    if (!mpegl_create_context(p->egl_display, p->log, flags, &p->egl_context,
+                              &config))
+        goto fail;
+
+    p->egl_window = (struct fbdev_window){
+        .width = p->w,
+        .height = p->h,
+    };
+
+    p->egl_surface = eglCreateWindowSurface(p->egl_display, config,
+                                    (EGLNativeWindowType)&p->egl_window, NULL);
+
+    if (p->egl_surface == EGL_NO_SURFACE) {
+        MP_FATAL(p, "Could not create EGL surface!\n");
+        goto fail;
+    }
+
+    if (!eglMakeCurrent(p->egl_display, p->egl_surface, p->egl_surface,
+                        p->egl_context))
+    {
+        MP_FATAL(p, "Failed to set context!\n");
+        goto fail;
+    }
+
+    ctx->gl = talloc_zero(ctx, GL);
+
+    const char *exts = eglQueryString(p->egl_display, EGL_EXTENSIONS);
+    mpgl_load_functions(ctx->gl, get_proc_address, exts, p->log);
+
+    return 0;
+
+fail:
+    mali_uninit(ctx);
+    return -1;
+}
+
+static int mali_reconfig(struct MPGLContext *ctx)
+{
+    struct priv *p = ctx->priv;
+    ctx->vo->dwidth = p->w;
+    ctx->vo->dheight = p->h;
+    return 0;
+}
+
+static void mali_swap_buffers(MPGLContext *ctx)
+{
+    struct priv *p = ctx->priv;
+    eglSwapBuffers(p->egl_display, p->egl_surface);
+}
+
+static int mali_control(MPGLContext *ctx, int *events, int request, void *arg)
+{
+    return VO_NOTIMPL;
+}
+
+const struct mpgl_driver mpgl_driver_mali = {
+    .name           = "mali-fbdev",
+    .priv_size      = sizeof(struct priv),
+    .init           = mali_init,
+    .reconfig       = mali_reconfig,
+    .swap_buffers   = mali_swap_buffers,
+    .control        = mali_control,
+    .uninit         = mali_uninit,
+};

wscript

@@ -822,11 +822,22 @@ video_output_features = [
         'deps': ['any-gl'],
         'deps_any': [ 'libmpv-shared', 'libmpv-static' ],
         'func': check_true,
+    }, {
+        'name': '--mali-fbdev',
+        'desc': 'MALI via Linux fbdev',
+        'deps': ['standard-gl', 'libdl'],
+        'func': compose_checks(
+            check_cc(lib="EGL"),
+            check_cc(lib="GLESv2"),
+            check_statement('EGL/fbdev_window.h', 'struct fbdev_window test'),
+            check_statement('linux/fb.h', 'struct fb_var_screeninfo test'),
+        ),
     }, {
         'name': '--gl',
         'desc': 'OpenGL video outputs',
         'deps_any': [ 'gl-cocoa', 'gl-x11', 'egl-x11', 'egl-drm',
-                      'gl-win32', 'gl-wayland', 'rpi', 'plain-gl' ],
+                      'gl-win32', 'gl-wayland', 'rpi', 'mali-fbdev',
+                      'plain-gl' ],
         'func': check_true,
         'req': True,
         'fmsg': "Unable to find OpenGL header files for video output. " +
@@ -835,7 +846,7 @@ video_output_features = [
     }, {
         'name': 'egl-helpers',
         'desc': 'EGL helper functions',
-        'deps_any': [ 'egl-x11' ],
+        'deps_any': [ 'egl-x11', 'mali-fbdev' ],
         'func': check_true
     }
 ]

wscript_build.py

@@ -334,6 +334,7 @@ def build(ctx):
         ( "video/out/opengl/context_cocoa.c",    "gl-cocoa" ),
         ( "video/out/opengl/context_drm_egl.c",  "egl-drm" ),
         ( "video/out/opengl/context_dxinterop.c","gl-dxinterop" ),
+        ( "video/out/opengl/context_mali_fbdev.c","mali-fbdev" ),
         ( "video/out/opengl/context_rpi.c",      "rpi" ),
         ( "video/out/opengl/context_wayland.c",  "gl-wayland" ),
         ( "video/out/opengl/context_w32.c",      "gl-win32" ),