tools: Add rudimentary dri3info

A simple tool just to check if the target Xserver offers dri3.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

tools/.gitignore

@@ -1,3 +1,4 @@
+dri3info
 intel-virtual-output
-xf86-video-intel-backlight-helper
 org.x.xf86-video-intel.backlight-helper.policy
+xf86-video-intel-backlight-helper

tools/Makefile.am

@@ -31,6 +31,12 @@ bin_PROGRAMS = intel-virtual-output
 driverman_DATA = intel-virtual-output.$(DRIVER_MAN_SUFFIX)
 endif
 
+if X11_DRI3
+noinst_PROGRAMS = dri3info
+dri3info_SOURCES = dri3info.c
+dri3info_LDADD = $(X11_DRI3_LIBS)
+endif
+
 if BUILD_BACKLIGHT_HELPER
 libexec_PROGRAMS = xf86-video-intel-backlight-helper
 nodist_policy_DATA = org.x.xf86-video-intel.backlight-helper.policy

tools/dri3info.c

@@ -0,0 +1,115 @@
+/*
+ * Copyright (c) 2015 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ */
+
+#include <X11/Xlib.h>
+#include <X11/Xlib-xcb.h>
+#include <xcb/xcb.h>
+#include <xcb/dri3.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+
+static int dri3_open(Display *dpy)
+{
+	xcb_connection_t *c = XGetXCBConnection(dpy);
+	xcb_dri3_open_cookie_t cookie;
+	xcb_dri3_open_reply_t *reply;
+
+	cookie = xcb_dri3_open(c, RootWindow(dpy, DefaultScreen(dpy)), None);
+	reply = xcb_dri3_open_reply(c, cookie, NULL);
+
+	if (!reply)
+		return -1;
+
+	if (reply->nfd != 1)
+		return -1;
+
+	return xcb_dri3_open_reply_fds(c, reply)[0];
+}
+
+static void match_device(int fd, char *buf, int len)
+{
+	struct stat remote, local;
+	int i;
+
+	if (fstat(fd, &remote))
+		goto out;
+
+	for (i = 0; i < 64; i++) {
+		snprintf(buf, len, "/dev/dri/card%d", i);
+		if (stat(buf, &local))
+			continue;
+
+		if (local.st_mode == remote.st_mode &&
+		    local.st_rdev == remote.st_rdev)
+			return;
+	}
+
+out:
+	strncpy(buf, "unknown card", len);
+}
+
+static void info(const char *dpyname)
+{
+	Display *dpy;
+	int device;
+	char device_name[1024];
+
+	dpy = XOpenDisplay(dpyname);
+	if (dpy == NULL) {
+		printf("Unable to connect to display '%s'\n",
+		       dpyname ?: getenv("DISPLAY") ?: "unset");
+		return;
+	}
+
+	device = dri3_open(dpy);
+	if (device < 0) {
+		printf("Unable to connect to DRI3 on display '%s'\n",
+		       DisplayString(dpy));
+		return;
+	}
+
+	match_device(device, device_name, sizeof(device_name));
+
+	printf("Connected to DRI3 on display '%s', using fd %d: matches %s\n",
+	       DisplayString(dpy), device, device_name);
+
+	XCloseDisplay(dpy);
+	close(device);
+}
+
+int main(int argc, char **argv)
+{
+	int i;
+
+	if (argc > 1) {
+		for (i = 1; i < argc; i++)
+			info(argv[i]);
+	} else
+		info(NULL);
+
+	return 0;
+}