kdrive/ephyr: Use NotifyFd for XCB connection input [v2]

Eliminates polling every 20ms for device input.

v2: rename ephyrPoll to ephyrXcbNotify and fix the API so it can be
    used directly for SetNotifyFd. Thanks to Daniel Martin
    <consume.noise@gmail.com>

Reviewed-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Keith Packard <keithp@keithp.com>
Cc: Daniel Martin <consume.noise@gmail.com>

hw/kdrive/ephyr/ephyr.c

@@ -1182,8 +1182,8 @@ ephyrProcessConfigureNotify(xcb_generic_event_t *xev)
 #endif /* RANDR */
 }
 
-void
-ephyrPoll(void)
+static void
+ephyrXcbNotify(int fd, int ready, void *data)
 {
     xcb_connection_t *conn = hostx_get_xcbconn();
 
@@ -1334,6 +1334,7 @@ static Status
 MouseEnable(KdPointerInfo * pi)
 {
     ((EphyrPointerPrivate *) pi->driverPrivate)->enabled = TRUE;
+    SetNotifyFd(hostx_get_fd(), ephyrXcbNotify, X_NOTIFY_READ, NULL);
     return Success;
 }
 
@@ -1341,6 +1342,7 @@ static void
 MouseDisable(KdPointerInfo * pi)
 {
     ((EphyrPointerPrivate *) pi->driverPrivate)->enabled = FALSE;
+    RemoveNotifyFd(hostx_get_fd());
     return;
 }
 

hw/kdrive/ephyr/ephyr.h

@@ -168,9 +168,6 @@ Bool
 Bool
  ephyrCreateColormap(ColormapPtr pmap);
 
-void
- ephyrPoll(void);
-
 #ifdef RANDR
 Bool
  ephyrRandRGetInfo(ScreenPtr pScreen, Rotation * rotations);

hw/kdrive/ephyr/hostx.c

@@ -1112,6 +1112,12 @@ hostx_get_screen(void)
     return HostX.screen;
 }
 
+int
+hostx_get_fd(void)
+{
+    return xcb_get_file_descriptor(HostX.conn);
+}
+
 int
 hostx_get_window(int a_screen_number)
 {

hw/kdrive/ephyr/hostx.h

@@ -198,4 +198,6 @@ int hostx_has_dri(void);
 int hostx_has_glx(void);
 #endif                          /* XF86DRI */
 
+int hostx_get_fd(void);
+
 #endif /*_XLIBS_STUFF_H_*/

hw/kdrive/ephyr/os.c

@@ -45,5 +45,4 @@ EphyrInit(void)
 
 KdOsFuncs EphyrOsFuncs = {
     .Init = EphyrInit,
-    .pollEvents = ephyrPoll,
 };