// SPDX-License-Identifier: BSD-3-Clause
/*
 * egl_retry.c - EGL/GLES2 offscreen probe with an explicit eglMakeCurrent
 * retry loop. The r581-era trace showed the glsi engine-init returning
 * 0xee00001 ("busy") exactly once and setting the device state bit 0x20;
 * eglcore does not retry. This probe retries the make-current (and the whole
 * display/context creation) up to N times, printing the precise EGL error of
 * every attempt, so we can tell "one-shot busy, retry succeeds" from
 * "permanent failure".
 *
 * Build (guest): gcc -O2 -o egl_retry egl_retry.c -lEGL -lGLESv2
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <EGL/egl.h>
#include <EGL/eglext.h>
#include <GLES2/gl2.h>

static EGLDisplay get_device_display(void)
{
	PFNEGLGETPLATFORMDISPLAYEXTPROC gp =
		(PFNEGLGETPLATFORMDISPLAYEXTPROC)eglGetProcAddress(
			"eglGetPlatformDisplayEXT");
	PFNEGLQUERYDEVICESEXTPROC qd =
		(PFNEGLQUERYDEVICESEXTPROC)eglGetProcAddress(
			"eglQueryDevicesEXT");
	EGLDeviceEXT devs[8];
	EGLint n = 0;

	if (!gp || !qd || !qd(8, devs, &n) || n <= 0)
		return EGL_NO_DISPLAY;
	printf("EGL_DEVICES n=%d\n", n);
	return gp(EGL_PLATFORM_DEVICE_EXT, devs[0], NULL);
}

int main(int argc, char **argv)
{
	int tries = argc > 1 ? atoi(argv[1]) : 10;
	EGLDisplay dpy;
	EGLint major = 0, minor = 0;
	EGLConfig cfg;
	EGLint ncfg = 0;
	EGLSurface surf;
	EGLContext ctx = EGL_NO_CONTEXT;
	EGLint attrs[] = {
		EGL_SURFACE_TYPE, EGL_PBUFFER_BIT,
		EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
		EGL_RED_SIZE, 8, EGL_GREEN_SIZE, 8, EGL_BLUE_SIZE, 8,
		EGL_ALPHA_SIZE, 8, EGL_NONE
	};
	EGLint pb[] = { EGL_WIDTH, 64, EGL_HEIGHT, 64, EGL_NONE };
	EGLint cattr[] = { EGL_CONTEXT_CLIENT_VERSION, 2, EGL_NONE };
	int i;

	setvbuf(stdout, NULL, _IONBF, 0);

	dpy = get_device_display();
	if (dpy == EGL_NO_DISPLAY) {
		printf("NO_DEVICE_DISPLAY\n");
		return 1;
	}
	if (!eglInitialize(dpy, &major, &minor)) {
		printf("EGL_INIT_FAIL 0x%x\n", eglGetError());
		return 1;
	}
	printf("EGL_INIT ok %d.%d vendor=%s\n", major, minor,
	       eglQueryString(dpy, EGL_VENDOR));
	if (!eglBindAPI(EGL_OPENGL_ES_API)) {
		printf("BIND_API_FAIL 0x%x\n", eglGetError());
		return 1;
	}
	if (!eglChooseConfig(dpy, attrs, &cfg, 1, &ncfg) || ncfg < 1) {
		printf("CHOOSE_CONFIG_FAIL 0x%x n=%d\n", eglGetError(), ncfg);
		return 1;
	}
	for (i = 0; i < tries; i++) {
		surf = eglCreatePbufferSurface(dpy, cfg, pb);
		if (surf == EGL_NO_SURFACE) {
			printf("TRY %d CREATE_SURFACE_FAIL 0x%x\n", i + 1,
			       eglGetError());
			usleep(200000);
			continue;
		}
		if (ctx == EGL_NO_CONTEXT) {
			ctx = eglCreateContext(dpy, cfg, EGL_NO_CONTEXT,
					       cattr);
			if (ctx == EGL_NO_CONTEXT) {
				printf("TRY %d CREATE_CTX_FAIL 0x%x\n", i + 1,
				       eglGetError());
				eglDestroySurface(dpy, surf);
				usleep(200000);
				continue;
			}
		}
		if (eglMakeCurrent(dpy, surf, surf, ctx)) {
			const char *rend = (const char *)glGetString(
				GL_RENDERER);
			const char *ver = (const char *)glGetString(
				GL_VERSION);
			printf("TRY %d CURRENT OK renderer=%s version=%s\n",
			       i + 1, rend ? rend : "?", ver ? ver : "?");
			/* draw one clear + readback so the pipeline runs */
			glClearColor(0.1f, 0.4f, 0.9f, 1.0f);
			glClear(GL_COLOR_BUFFER_BIT);
			{
				unsigned char px[4];
				glReadPixels(0, 0, 1, 1, GL_RGBA,
					     GL_UNSIGNED_BYTE, px);
				printf("PIXEL %02x%02x%02x%02x\n", px[0],
				       px[1], px[2], px[3]);
			}
			printf("EGL_RETRY_OK on try %d\n", i + 1);
			return 0;
		}
		printf("TRY %d MAKE_CURRENT_FAIL 0x%x\n", i + 1,
		       eglGetError());
		eglDestroySurface(dpy, surf);
		usleep(200000);
	}
	printf("EGL_RETRY_EXHAUSTED tries=%d\n", tries);
	return 1;
}