x11: use xrandr to retrieve display refresh rate

Drop use of the ancient XF86VM, and use the slightly less ancient Xrandr
extension to retrieve the refresh rate. Xrandr has the advantage that it
supports multiple monitors (at least the modern version of it).

For now, we don't attempt any dynamic reconfiguration. We don't request
and listen to Xrandr events, and we don't notify the VO code of changes
in the refresh rate. (The later works by assuming that X coordinates map
directly to Xrandr coordinates, which probably is wrong with compositing
window manager, at least if these use complicated transformations. But I
know of no API to handle this.)

It would be nice to drop use of the Xinerama extension too, but
unfortunately, at least one EWMH feature uses Xinerama screen numbers,
and I don't know how that maps to Xrandr outputs.

1 files changed, 66 insertions, 18 deletions

diff --git a/video/out/x11_common.c b/video/out/x11_common.c
index ef72fb4ca7..7863506cf3 100644
--- a/video/out/x11_common.c
+++ b/video/out/x11_common.c
@@ -59,14 +59,14 @@
 #include <X11/extensions/Xinerama.h>
 #endif
 
-#if HAVE_XF86VM
-#include <X11/extensions/xf86vmode.h>
-#endif
-
 #if HAVE_XF86XK
 #include <X11/XF86keysym.h>
 #endif
 
+#if HAVE_XRANDR
+#include <X11/extensions/Xrandr.h>
+#endif
+
 #if HAVE_ZLIB
 #include <zlib.h>
 #endif
@@ -325,6 +325,50 @@ static int vo_wm_detect(struct vo *vo)
     return wm;
 }
 
+static void xrandr_read(struct vo_x11_state *x11)
+{
+#ifdef HAVE_XRANDR
+    x11->num_displays = 0;
+
+    XRRScreenResources *r = XRRGetScreenResources(x11->display, x11->rootwin);
+    if (!r) {
+        MP_VERBOSE(x11, "Xrandr doesn't work.\n");
+        return;
+    }
+
+    for (int o = 0; o < r->noutput; o++) {
+        RROutput output = r->outputs[o];
+        XRROutputInfo *out = XRRGetOutputInfo(x11->display, r, output);
+        if (!out || !out->crtc)
+            continue;
+        XRRCrtcInfo *crtc = XRRGetCrtcInfo(x11->display, r, out->crtc);
+        if (!crtc)
+            continue;
+        for (int om = 0; om < out->nmode; om++) {
+            RRMode xm = out->modes[om];
+            for (int n = 0; n < r->nmode; n++) {
+                XRRModeInfo m = r->modes[n];
+                if (m.id != xm || crtc->mode != xm)
+                    continue;
+                if (x11->num_displays >= MAX_DISPLAYS)
+                    continue;
+                struct xrandr_display d = {
+                    .rc = { crtc->x, crtc->y,
+                            crtc->x + crtc->width, crtc->y + crtc->height },
+                    .fps = m.dotClock / (m.hTotal * (double)m.vTotal),
+                };
+                int num = x11->num_displays++;
+                MP_VERBOSE(x11, "Display %d: [%d, %d, %d, %d] @ %f FPS\n",
+                           num, d.rc.x0, d.rc.y0, d.rc.x1, d.rc.y1, d.fps);
+                x11->displays[num] = d;
+            }
+        }
+    }
+
+    XRRFreeScreenResources(r);
+#endif
+}
+
 static void vo_x11_update_screeninfo(struct vo *vo)
 {
     struct mp_vo_opts *opts = vo->opts;
@@ -456,6 +500,8 @@ int vo_x11_init(struct vo *vo)
 
     vo->event_fd = ConnectionNumber(x11->display);
 
+    xrandr_read(x11);
+
     return 1;
 }
 
@@ -1359,6 +1405,11 @@ static void vo_x11_setlayer(struct vo *vo, bool ontop)
     }
 }
 
+static bool rc_overlaps(struct mp_rect rc1, struct mp_rect rc2)
+{
+    return mp_rect_intersection(&rc1, &rc2); // changes the first argument
+}
+
 // update x11->winrc with current boundaries of vo->x11->window
 static void vo_x11_update_geometry(struct vo *vo)
 {
@@ -1379,6 +1430,16 @@ static void vo_x11_update_geometry(struct vo *vo)
                               &x, &y, &dummy_win);
     }
     x11->winrc = (struct mp_rect){x, y, x + w, y + h};
+    double fps = 1000.0;
+    for (int n = 0; n < x11->num_displays; n++) {
+        if (rc_overlaps(x11->displays[n].rc, x11->winrc))
+            fps = MPMIN(fps, x11->displays[n].fps);
+    }
+    double fallback = x11->num_displays > 0 ? x11->displays[0].fps : 0;
+    fps = fps < 1000.0 ? fps : fallback;
+    if (fps != x11->current_display_fps)
+        MP_VERBOSE(x11, "Current display FPS: %f\n", fps);
+    x11->current_display_fps = fps;
 }
 
 static void vo_x11_fullscreen(struct vo *vo)
@@ -1596,24 +1657,11 @@ static void vo_x11_selectinput_witherr(struct vo *vo,
     }
 }
 
-#if HAVE_XF86VM
 double vo_x11_vm_get_fps(struct vo *vo)
 {
     struct vo_x11_state *x11 = vo->x11;
-    int clock;
-    XF86VidModeModeLine modeline;
-    if (!XF86VidModeGetModeLine(x11->display, x11->screen, &clock, &modeline))
-        return 0;
-    if (modeline.privsize)
-        XFree(modeline.private);
-    return 1e3 * clock / modeline.htotal / modeline.vtotal;
+    return x11->current_display_fps;
 }
-#else /* HAVE_XF86VM */
-double vo_x11_vm_get_fps(struct vo *vo)
-{
-    return 0;
-}
-#endif
 
 bool vo_x11_screen_is_composited(struct vo *vo)
 {