From cbb31f2d6e674513c0f66484c414475baba09153 Mon Sep 17 00:00:00 2001
From: Robert Millan <rmh@freebsd.org>
Date: Thu, 23 Jan 2014 14:46:05 +0000
Subject: [PATCH] drm: Implement drmCheckModesettingSupported() for FreeBSD

Add the missing implementation of drmCheckModesettingSupported()
to detect KMS support on FreeBSD (and GNU/kFreeBSD).

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=72847
Signed-off-by: Konstantin Belousov <kib@freebsd.org>
Signed-off-by: Robert Millan <rmh@freebsd.org>
---
 configure.ac  |  2 ++
 xf86drmMode.c | 35 ++++++++++++++++++++++++++++++++++-
 2 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index 969fb83b..d2d19d66 100644
--- a/configure.ac
+++ b/configure.ac
@@ -185,6 +185,8 @@ AC_CANONICAL_HOST
 if test "x$LIBKMS" = xauto ; then
 	case $host_os in
 		linux*)		LIBKMS="yes" ;;
+		freebsd* | kfreebsd*-gnu)
+				LIBKMS="yes" ;;
 		*)		LIBKMS="no" ;;
 	esac
 fi
diff --git a/xf86drmMode.c b/xf86drmMode.c
index dd7966ef..a6bb2ee4 100644
--- a/xf86drmMode.c
+++ b/xf86drmMode.c
@@ -723,7 +723,7 @@ int drmModeConnectorSetProperty(int fd, uint32_t connector_id, uint32_t property
 */
 int drmCheckModesettingSupported(const char *busid)
 {
-#ifdef __linux__
+#if defined (__linux__)
 	char pci_dev_dir[1024];
 	int domain, bus, dev, func;
 	DIR *sysdir;
@@ -773,6 +773,39 @@ int drmCheckModesettingSupported(const char *busid)
 	closedir(sysdir);
 	if (found)
 		return 0;
+#elif defined (__FreeBSD__) || defined (__FreeBSD_kernel__)
+	char kbusid[1024], sbusid[1024];
+	char oid[128];
+	int domain, bus, dev, func;
+	int i, modesetting, ret;
+	size_t len;
+
+	ret = sscanf(busid, "pci:%04x:%02x:%02x.%d", &domain, &bus, &dev,
+	    &func);
+	if (ret != 4)
+		return -EINVAL;
+	snprintf(kbusid, sizeof(kbusid), "pci:%04x:%02x:%02x.%d", domain, bus,
+	    dev, func);
+
+	/* How many GPUs do we expect in the machine ? */
+	for (i = 0; i < 16; i++) {
+		snprintf(oid, sizeof(oid), "hw.dri.%d.busid", i);
+		len = sizeof(sbusid);
+		ret = sysctlbyname(oid, sbusid, &len, NULL, 0);
+		if (ret == -1) {
+			if (errno == ENOENT)
+				continue;
+			return -EINVAL;
+		}
+		if (strcmp(sbusid, kbusid) != 0)
+			continue;
+		snprintf(oid, sizeof(oid), "hw.dri.%d.modesetting", i);
+		len = sizeof(modesetting);
+		ret = sysctlbyname(oid, &modesetting, &len, NULL, 0);
+		if (ret == -1 || len != sizeof(modesetting))
+			return -EINVAL;
+		return (modesetting ? 0 : -ENOSYS);
+	}
 #endif
 	return -ENOSYS;