modesetting: Detect changes to the _VARIABLE_REFRESH window properties

Window wrappers gets the notification when the window
properties changes. These wrappers are mainly used to
keep track of per-window _VARIABLE_REFRESH property values.

These changes have been ported from AMDGPU

Signed-off-by: Uday Kiran Pichika <pichika.uday.kiran@intel.com>

hw/xfree86/drivers/modesetting/driver.c

@@ -80,6 +80,14 @@ static Bool ms_pci_probe(DriverPtr driver,
                          intptr_t match_data);
 static Bool ms_driver_func(ScrnInfoPtr scrn, xorgDriverFuncOp op, void *data);
 
+/* window wrapper functions used to get the notification when
+ * the window property changes */
+static Atom vrr_atom;
+static Bool property_vectors_wrapped;
+static Bool restore_property_vector;
+static int (*saved_change_property) (ClientPtr client);
+static int (*saved_delete_property) (ClientPtr client);
+
 #ifdef XSERVER_LIBPCIACCESS
 static const struct pci_id_match ms_device_match[] = {
     {
@@ -712,6 +720,126 @@ ms_window_has_variable_refresh(modesettingPtr ms, WindowPtr win) {
 
 	return priv->variable_refresh;
 }
+
+static void
+ms_vrr_property_update(WindowPtr window, Bool variable_refresh)
+{
+    ScrnInfoPtr scrn = xf86ScreenToScrn(window->drawable.pScreen);
+    modesettingPtr ms = modesettingPTR(scrn);
+
+    struct ms_vrr_priv *priv = dixLookupPrivate(&window->devPrivates,
+                                                &ms->drmmode.vrrPrivateKeyRec);
+    priv->variable_refresh = variable_refresh;
+
+    if (ms->flip_window == window && ms->drmmode.present_flipping)
+        ms_present_set_screen_vrr(scrn, variable_refresh);
+}
+
+/* Wrapper for xserver/dix/property.c:ProcChangeProperty */
+static int
+ms_change_property(ClientPtr client)
+{
+    WindowPtr window = NULL;
+    int ret = 0;
+
+    REQUEST(xChangePropertyReq);
+
+    client->requestVector[X_ChangeProperty] = saved_change_property;
+    ret = saved_change_property(client);
+    if (ret != Success)
+        return ret;
+
+    if (restore_property_vector)
+        return ret;
+
+    client->requestVector[X_ChangeProperty] = ms_change_property;
+
+    ret = dixLookupWindow(&window, stuff->window, client, DixSetPropAccess);
+    if (ret != Success)
+        return ret;
+
+    // Checking for the VRR property change on the window
+    if (stuff->property == vrr_atom &&
+        xf86ScreenToScrn(window->drawable.pScreen)->PreInit == PreInit &&
+        stuff->format == 32 && stuff->nUnits == 1) {
+        uint32_t *value = (uint32_t *)(stuff + 1);
+        ms_vrr_property_update(window, *value != 0);
+    }
+
+    return ret;
+}
+
+/* Wrapper for xserver/dix/property.c:ProcDeleteProperty */
+static int
+ms_delete_property(ClientPtr client)
+{
+    WindowPtr window;
+    int ret;
+
+    REQUEST(xDeletePropertyReq);
+
+    client->requestVector[X_DeleteProperty] = saved_delete_property;
+    ret = saved_delete_property(client);
+
+    if (restore_property_vector)
+        return ret;
+
+    client->requestVector[X_DeleteProperty] = ms_delete_property;
+
+    if (ret != Success)
+        return ret;
+
+    ret = dixLookupWindow(&window, stuff->window, client, DixSetPropAccess);
+    if (ret != Success)
+        return ret;
+
+    if (stuff->property == vrr_atom &&
+        xf86ScreenToScrn(window->drawable.pScreen)->PreInit == PreInit)
+        ms_vrr_property_update(window, FALSE);
+
+    return ret;
+}
+
+static void
+ms_unwrap_property_requests(ScrnInfoPtr scrn)
+{
+    int i;
+
+    if (!property_vectors_wrapped)
+        return;
+
+    if (ProcVector[X_ChangeProperty] == ms_change_property)
+        ProcVector[X_ChangeProperty] = saved_change_property;
+    else
+        restore_property_vector = TRUE;
+
+    if (ProcVector[X_DeleteProperty] == ms_delete_property)
+        ProcVector[X_DeleteProperty] = saved_delete_property;
+    else
+        restore_property_vector = TRUE;
+
+    for (i = 0; i < currentMaxClients; i++) {
+        if (clients[i]->requestVector[X_ChangeProperty] == ms_change_property) {
+            clients[i]->requestVector[X_ChangeProperty] = saved_change_property;
+        } else {
+            restore_property_vector = TRUE;
+        }
+
+        if (clients[i]->requestVector[X_DeleteProperty] == ms_delete_property) {
+            clients[i]->requestVector[X_DeleteProperty] = saved_delete_property;
+        } else {
+            restore_property_vector = TRUE;
+        }
+    }
+
+    if (restore_property_vector) {
+        xf86DrvMsg(scrn->scrnIndex, X_WARNING,
+                   "Couldn't unwrap some window property request vectors\n");
+    }
+
+    property_vectors_wrapped = FALSE;
+}
+
 static void
 FreeRec(ScrnInfoPtr pScrn)
 {
@@ -731,6 +859,7 @@ FreeRec(ScrnInfoPtr pScrn)
         ms_ent = ms_ent_priv(pScrn);
         ms_ent->fd_ref--;
         if (!ms_ent->fd_ref) {
+            ms_unwrap_property_requests(pScrn);
             if (ms->pEnt->location.type == BUS_PCI)
                 ret = drmClose(ms->fd);
             else
@@ -1817,6 +1946,18 @@ ScreenInit(ScreenPtr pScreen, int argc, char **argv)
 
     pScrn->vtSema = TRUE;
 
+    if (ms->vrr_support) {
+        if (!property_vectors_wrapped) {
+            saved_change_property = ProcVector[X_ChangeProperty];
+            ProcVector[X_ChangeProperty] = ms_change_property;
+            saved_delete_property = ProcVector[X_DeleteProperty];
+            ProcVector[X_DeleteProperty] = ms_delete_property;
+            property_vectors_wrapped = TRUE;
+        }
+        vrr_atom = MakeAtom("_VARIABLE_REFRESH",
+                             strlen("_VARIABLE_REFRESH"), TRUE);
+    }
+
     return TRUE;
 }