Restore valuator values after receiving a DeviceChanged event

* src/xterm.c (x_init_master_valuators): Generate valuators for
both master and slave devices.
(handle_one_xevent): Find current valuator info and use that to
populate scroll valuators after a device changed.

1 files changed, 40 insertions, 24 deletions

diff --git a/src/xterm.c b/src/xterm.c
index 198aaa69e5f..98c8a224080 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -631,16 +631,13 @@ x_init_master_valuators (struct x_display_info *dpyinfo)
                       (XIScrollClassInfo *) device->classes[c];
                     struct xi_scroll_valuator_t *valuator;
 
-                    if (xi_device->master_p)
-                      {
-                        valuator = &xi_device->valuators[actual_valuator_count++];
-                        valuator->horizontal
-                          = (info->scroll_type == XIScrollTypeHorizontal);
-                        valuator->invalid_p = true;
-                        valuator->emacs_value = DBL_MIN;
-                        valuator->increment = info->increment;
-                        valuator->number = info->number;
-                      }
+                    valuator = &xi_device->valuators[actual_valuator_count++];
+                    valuator->horizontal
+                      = (info->scroll_type == XIScrollTypeHorizontal);
+                    valuator->invalid_p = true;
+                    valuator->emacs_value = DBL_MIN;
+                    valuator->increment = info->increment;
+                    valuator->number = info->number;
 
                     break;
                   }
@@ -11872,9 +11869,9 @@ handle_one_xevent (struct x_display_info *dpyinfo,
             {
               struct xi_device_t *device;
               struct xi_touch_point_t *tem, *last;
-              int c;
+              int c, i;
 
-              device = xi_device_from_id (dpyinfo, device_changed->sourceid);
+              device = xi_device_from_id (dpyinfo, device_changed->deviceid);
 
               if (!device)
                 emacs_abort ();
@@ -11894,20 +11891,18 @@ handle_one_xevent (struct x_display_info *dpyinfo,
 #ifdef XIScrollClass
                     case XIScrollClass:
                       {
-                        XIScrollClassInfo *info =
-                          (XIScrollClassInfo *) device_changed->classes[c];
+                        XIScrollClassInfo *info;
+
+                        info = (XIScrollClassInfo *) device_changed->classes[c];
                         struct xi_scroll_valuator_t *valuator;
 
-                        if (device->master_p)
-                          {
-                            valuator = &device->valuators[device->scroll_valuator_count++];
-                            valuator->horizontal
-                              = (info->scroll_type == XIScrollTypeHorizontal);
-                            valuator->invalid_p = true;
-                            valuator->emacs_value = DBL_MIN;
-                            valuator->increment = info->increment;
-                            valuator->number = info->number;
-                          }
+                        valuator = &device->valuators[device->scroll_valuator_count++];
+                        valuator->horizontal
+                          = (info->scroll_type == XIScrollTypeHorizontal);
+                        valuator->invalid_p = true;
+                        valuator->emacs_value = DBL_MIN;
+                        valuator->increment = info->increment;
+                        valuator->number = info->number;
 
                         break;
                       }
@@ -11927,6 +11922,27 @@ handle_one_xevent (struct x_display_info *dpyinfo,
                     }
                 }
 
+#ifdef XIScrollClass
+              for (c = 0; c < device_changed->num_classes; ++c)
+                {
+                  if (device_changed->classes[c]->type == XIValuatorClass)
+                    {
+                      XIValuatorClassInfo *info;
+
+                      info = (XIValuatorClassInfo *) device_changed->classes[c];
+
+                      for (i = 0; i < device->scroll_valuator_count; ++i)
+                        {
+                          if (device->valuators[i].number == info->number)
+                            {
+                              device->valuators[i].invalid_p = false;
+                              device->valuators[i].current_value = info->value;
+                            }
+                        }
+                    }
+                }
+#endif
+
               /* The device is no longer a DirectTouch device, so
                  remove any touchpoints that we might have
                  recorded.  */