Document how to autodetect with gudev
Signed-off-by: Linus Walleij <triad@df.lth.se>
diff --git a/README b/README
index bca8bfa..28ef5a2 100644
--- a/README
+++ b/README
@@ -762,3 +762,82 @@
set-top-boxes etc. It will be very irritating for customers if a device
will not dock properly with some home entertainment equipment just because
it is based on Linux and libmtp and not the Windows MTP stack.
+
+Autodetect with gudev
+---------------------
+
+Previously you would use HAL to detect devices being plugged in. Nowadays
+we use udev directly, or though the GNOME libgudev library. LIBMTPs
+default udev rules export the proper properties to detect any MTP device
+automatically, here is a verbose example derived from gnomad2:
+
+#define G_UDEV_API_IS_SUBJECT_TO_CHANGE
+#include <gudev/gudev.h>
+const char * const gudev_subsystems[] = { "usb", NULL };
+GUdevClient *gudev_client;
+guint uevent_id;
+guint uevent_bus_hooked = 0;
+guint uevent_device_hooked = 0;
+
+
+static void uevent_cb(GUdevClient *client, const char *action, GUdevDevice *device, void *data)
+{
+ guint64 devicenum;
+ guint vendor;
+ guint model;
+ guint busnum;
+ guint devnum;
+ guint mtpdevice;
+
+ devicenum = (guint64) g_udev_device_get_device_number(device);
+ g_print("%s event for %s (%"G_GINT64_MODIFIER"x)", action,
+ g_udev_device_get_sysfs_path (device), devicenum);
+
+ /* get device info */
+ vendor = get_property_as_int(device, "ID_VENDOR_ID", 16);
+ model = get_property_as_int(device, "ID_MODEL_ID", 16);
+ busnum = get_property_as_int(device, "BUSNUM", 10);
+ devnum = get_property_as_int(device, "DEVNUM", 10);
+ mtpdevice = get_property_as_int(device, "ID_MTP_DEVICE", 10);
+
+ if (vendor == 0 || model == 0) {
+ g_print("couldn't get vendor or model ID for device at (%x:%x)\n",
+ busnum, devnum);
+ return;
+ } else {
+ g_print("vendor = %x, model = %x, bus = %x, device = %x\n",
+ vendor, model, busnum, devnum);
+ }
+
+ if (mtpdevice) {
+ g_print("device is MTP compliant\n");
+
+ if (g_str_equal(action, "add") &&
+ uevent_bus_hooked == 0 &&
+ uevent_device_hooked == 0) {
+ g_print(MTP device plugged in!\n");
+ uevent_bus_hooked = busnum;
+ uevent_device_hooked = devnum;
+ scan_jukebox(NULL);
+ } else if (g_str_equal (action, "remove") &&
+ uevent_bus_hooked == busnum &&
+ uevent_device_hooked == devnum) {
+ g_print("MTP device removed!\n");
+ uevent_bus_hooked = 0;
+ uevent_device_hooked = 0;
+ }
+ }
+}
+
+
+
+(...)
+ /*
+ * Monitor udev device events - we're only really interested in events
+ * for USB devices.
+ */
+ gudev_client = g_udev_client_new(gudev_subsystems);
+ uevent_id = g_signal_connect_object(gudev_client,
+ "uevent",
+ G_CALLBACK(uevent_cb),
+ NULL, 0);