intel: Listen for hotplug uevents (V3)

This connects the kernel uevent indicating monitor hotplugging to the
RandR notification events so that X applications can be notified
automatically when monitors are connected or disconnected.

This also adds a configuration option to disable hotplug events.

V2: missed a #ifdef HAVE_UDEV around some udev-specific declarations

V3: document Hotplug option in man page

Signed-off-by: Keith Packard <keithp@keithp.com>

3 files changed, 128 insertions, 2 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index 7d823ce3..abb03c3f 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -26,13 +26,13 @@ SUBDIRS = xvmc render_program legacy
 # _ladir passes a dummy rpath to libtool so the thing will actually link
 # TODO: -nostdlib/-Bstatic/-lgcc platform magic, not installing the .a, etc.
 
-AM_CFLAGS = @CWARNFLAGS@ @XORG_CFLAGS@ @DRM_CFLAGS@ @DRI_CFLAGS@ \
+AM_CFLAGS = @CWARNFLAGS@ @XORG_CFLAGS@ @UDEV_CFLAGS@ @DRM_CFLAGS@ @DRI_CFLAGS@ \
 	@PCIACCESS_CFLAGS@ -I$(top_srcdir)/uxa -I$(top_srcdir)/src/render_program
 
 intel_drv_la_LTLIBRARIES = intel_drv.la
 intel_drv_la_LDFLAGS = -module -avoid-version
 intel_drv_ladir = @moduledir@/drivers
-intel_drv_la_LIBADD = -lm @DRM_LIBS@ -ldrm_intel ../uxa/libuxa.la legacy/liblegacy.la
+intel_drv_la_LIBADD = @UDEV_LIBS@ -lm @DRM_LIBS@ -ldrm_intel ../uxa/libuxa.la legacy/liblegacy.la
 intel_drv_la_LIBADD += @PCIACCESS_LIBS@
 
 NULL:=#
diff --git a/src/intel.h b/src/intel.h
index 6b059976..7604eeea 100644
--- a/src/intel.h
+++ b/src/intel.h
@@ -34,6 +34,10 @@ SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  *
  */
 
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
 #if 0
 #define I830DEBUG
 #endif
@@ -70,6 +74,10 @@ SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 #include "intel_driver.h"
 
+#if HAVE_UDEV
+#include <libudev.h>
+#endif
+
 #include "uxa.h"
 /* XXX
  * The X server gained an *almost* identical implementation in 1.9.
@@ -441,6 +449,10 @@ typedef struct intel_screen_private {
 	 */
 	Bool fallback_debug;
 	unsigned debug_flush;
+#if HAVE_UDEV
+	struct udev_monitor *uevent_monitor;
+	InputHandlerProc uevent_handler;
+#endif
 } intel_screen_private;
 
 enum {
diff --git a/src/intel_driver.c b/src/intel_driver.c
index b16913b4..7e4a4a43 100644
--- a/src/intel_driver.c
+++ b/src/intel_driver.c
@@ -107,6 +107,7 @@ typedef enum {
    OPTION_DEBUG_FLUSH_BATCHES,
    OPTION_DEBUG_FLUSH_CACHES,
    OPTION_DEBUG_WAIT,
+   OPTION_HOTPLUG,
 } I830Opts;
 
 static OptionInfoRec I830Options[] = {
@@ -125,6 +126,7 @@ static OptionInfoRec I830Options[] = {
    {OPTION_DEBUG_FLUSH_BATCHES, "DebugFlushBatches", OPTV_BOOLEAN, {0}, FALSE},
    {OPTION_DEBUG_FLUSH_CACHES, "DebugFlushCaches", OPTV_BOOLEAN, {0}, FALSE},
    {OPTION_DEBUG_WAIT, "DebugWait", OPTV_BOOLEAN, {0}, FALSE},
+   {OPTION_HOTPLUG,	"HotPlug",	OPTV_BOOLEAN,	{0},	TRUE},
    {-1,			NULL,		OPTV_NONE,	{0},	FALSE}
 };
 /* *INDENT-ON* */
@@ -804,6 +806,110 @@ intel_flush_callback(CallbackListPtr *list,
 	}
 }
 
+#if HAVE_UDEV
+static void
+I830HandleUEvents(int fd, void *closure)
+{
+    ScrnInfoPtr scrn = closure;
+	intel_screen_private *intel = intel_get_screen_private(scrn);
+    struct udev_device *dev;
+    const char *hotplug;
+    struct stat s;
+    dev_t udev_devnum;
+
+    dev = udev_monitor_receive_device(intel->uevent_monitor);
+    if (!dev)
+	return;
+
+    udev_devnum = udev_device_get_devnum(dev);
+    fstat(intel->drmSubFD, &s);
+    /*
+     * Check to make sure this event is directed at our
+     * device (by comparing dev_t values), then make
+     * sure it's a hotplug event (HOTPLUG=1)
+     */
+
+    hotplug = udev_device_get_property_value(dev, "HOTPLUG");
+
+    if (memcmp(&s.st_rdev, &udev_devnum, sizeof (dev_t)) == 0 &&
+	hotplug && atoi(hotplug) == 1)
+	RRGetInfo(screenInfo.screens[scrn->scrnIndex], TRUE);
+
+    udev_device_unref(dev);
+}
+
+static void
+I830UeventInit(ScrnInfoPtr scrn)
+{
+    intel_screen_private *intel = intel_get_screen_private(scrn);
+    struct udev *u;
+    struct udev_monitor *mon;
+    Bool hotplug;
+    MessageType from = X_CONFIG;
+
+    if (!xf86GetOptValBool(intel->Options, OPTION_HOTPLUG, &hotplug)) {
+	from = X_DEFAULT;
+	hotplug = TRUE;
+    }
+
+    xf86DrvMsg(scrn->scrnIndex, from, "hotplug detection: \"%s\"\n",
+	       hotplug ? "enabled" : "disabled");
+    if (!hotplug)
+	return;
+
+    u = udev_new();
+    if (!u)
+	return;
+
+    mon = udev_monitor_new_from_netlink(u, "udev");
+
+    if (!mon) {
+	udev_unref(u);
+	return;
+    }
+
+    if (udev_monitor_filter_add_match_subsystem_devtype(mon,
+							"drm",
+							"drm_minor") < 0 ||
+	udev_monitor_enable_receiving(mon) < 0)
+    {
+	udev_monitor_unref(mon);
+	udev_unref(u);
+	return;
+    }
+
+    intel->uevent_handler =
+	xf86AddGeneralHandler(udev_monitor_get_fd(mon),
+			      I830HandleUEvents,
+			      scrn);
+    if (!intel->uevent_handler) {
+	udev_monitor_unref(mon);
+	udev_unref(u);
+	return;
+    }
+
+    intel->uevent_monitor = mon;
+}
+
+static void
+I830UeventFini(ScrnInfoPtr scrn)
+{
+    intel_screen_private *intel = intel_get_screen_private(scrn);
+
+    if (intel->uevent_handler)
+    {
+	struct udev *u = udev_monitor_get_udev(intel->uevent_monitor);
+
+	xf86RemoveGeneralHandler(intel->uevent_handler);
+
+	udev_monitor_unref(intel->uevent_monitor);
+	udev_unref(u);
+	intel->uevent_handler = NULL;
+	intel->uevent_monitor = NULL;
+    }
+}
+#endif /* HAVE_UDEV */
+
 static Bool
 I830ScreenInit(int scrnIndex, ScreenPtr screen, int argc, char **argv)
 {
@@ -1010,6 +1116,10 @@ I830ScreenInit(int scrnIndex, ScreenPtr screen, int argc, char **argv)
 
 	intel->suspended = FALSE;
 
+#if HAVE_UDEV
+	I830UeventInit(scrn);
+#endif
+
 	return uxa_resources_init(screen);
 }
 
@@ -1091,6 +1201,10 @@ static Bool I830CloseScreen(int scrnIndex, ScreenPtr screen)
 	ScrnInfoPtr scrn = xf86Screens[scrnIndex];
 	intel_screen_private *intel = intel_get_screen_private(scrn);
 
+#if HAVE_UDEV
+	I830UeventFini(scrn);
+#endif
+
 	if (scrn->vtSema == TRUE) {
 		I830LeaveVT(scrnIndex, 0);
 	}