From 5ce95e92d5ec4e4a53abeb6a0f8f843781a4322e Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Mon, 23 Jun 2014 16:14:28 +0100
Subject: [PATCH] intel: Wait for the DRM device to load

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=80397
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 src/intel_device.c | 97 +++++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 81 insertions(+), 16 deletions(-)

diff --git a/src/intel_device.c b/src/intel_device.c
index d9d8df3..431905a 100644
--- a/src/intel_device.c
+++ b/src/intel_device.c
@@ -35,6 +35,7 @@
 #include <unistd.h>
 #include <fcntl.h>
 #include <stdlib.h>
+#include <dirent.h>
 #include <errno.h>
 
 #include <pciaccess.h>
@@ -162,32 +163,96 @@ static int __intel_check_device(int fd)
 	return ret;
 }
 
-static int __intel_open_device(const struct pci_device *pci, const char *path)
+static int __intel_open_device__pci(const struct pci_device *pci)
 {
+#ifdef __linux__
+	char path[256];
+	DIR *dir;
+	struct dirent *de;
+	int base;
 	int fd;
 
-	if (path == NULL) {
-		char id[20];
-		int ret;
-
-		if (pci == NULL)
-			return -1;
+	base = sprintf(path,
+		       "/sys/bus/pci/devices/%04x:%02x:%02x.%d/",
+		       pci->domain, pci->bus, pci->dev, pci->func);
 
-		snprintf(id, sizeof(id),
-			 "pci:%04x:%02x:%02x.%d",
-			 pci->domain, pci->bus, pci->dev, pci->func);
+	sprintf(path + base, "drm");
+	dir = opendir(path);
+	if (dir == NULL) {
+		struct stat st;
+		int loop = 0;
 
-		ret = drmCheckModesettingSupported(id);
-		if (ret) {
+		sprintf(path + base, "driver");
+		if (stat(path, &st)) {
 			if (xf86LoadKernelModule("i915"))
-				ret = drmCheckModesettingSupported(id);
-			if (ret)
 				return -1;
-			/* Be nice to the user and load fbcon too */
 			(void)xf86LoadKernelModule("fbcon");
 		}
 
-		fd = fd_set_nonblock(drmOpen(NULL, id));
+		sprintf(path + base, "drm");
+		while ((dir = opendir(path)) == NULL && loop++ < 100)
+			usleep(20000);
+
+		ErrorF("waited %d ms for driver to load\n", loop * 20000 / 1000);
+
+		if (dir == NULL)
+			return -1;
+	}
+
+	fd = -1;
+	de = readdir(dir);
+	while (de) {
+		if (strncmp(de->d_name, "card", 4) == 0) {
+			sprintf(path + base + 3, "/%s", de->d_name);
+#ifdef O_CLOEXEC
+			fd = open(path, O_RDWR | O_NONBLOCK | O_CLOEXEC);
+#endif
+			if (fd == -1)
+				fd = fd_set_cloexec(open(path, O_RDWR | O_NONBLOCK));
+			break;
+		}
+	}
+	closedir(dir);
+
+	return fd;
+#else
+	return -1;
+#endif
+}
+
+static int __intel_open_device__legacy(const struct pci_device *pci)
+{
+	char id[20];
+	int ret;
+
+	snprintf(id, sizeof(id),
+			"pci:%04x:%02x:%02x.%d",
+			pci->domain, pci->bus, pci->dev, pci->func);
+
+	ret = drmCheckModesettingSupported(id);
+	if (ret) {
+		if (xf86LoadKernelModule("i915"))
+			ret = drmCheckModesettingSupported(id);
+		if (ret)
+			return -1;
+		/* Be nice to the user and load fbcon too */
+		(void)xf86LoadKernelModule("fbcon");
+	}
+
+	return fd_set_nonblock(drmOpen(NULL, id));
+}
+
+static int __intel_open_device(const struct pci_device *pci, const char *path)
+{
+	int fd;
+
+	if (path == NULL) {
+		if (pci == NULL)
+			return -1;
+
+		fd = __intel_open_device__pci(pci);
+		if (fd == -1)
+			fd = __intel_open_device__legacy(pci);
 	} else {
 #ifdef O_CLOEXEC
 		fd = open(path, O_RDWR | O_NONBLOCK | O_CLOEXEC);
-- 
1.9.1