[PATCH v2 evdev] Make the slot-state per slot

[Peter Hutterer]

The previous approach only had the slot state for the current slot. If we
changed slots, that means we lost the information if the slot was ever
initialized. If the ABS_MT_TRACKING_ID was never received, the slot would
still update and try to send events (which the server refused with a warning).

Avoid this by having a per-slot state and a dirty bit that tells us if the
current slot updated at all. If we don't get the tracking ID, leave the slot
empty and refuse any further events from that touch.

This quashes the various "unable to find touch point 0" warnings caused if a
touchpoint starts before the device is enabled.

Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
---
Changes to v1:
- replace the convoluted if/else with a switch

 src/evdev.c | 75 +++++++++++++++++++++++++++++++++++++++----------------------
 src/evdev.h |  5 ++++-
 2 files changed, 52 insertions(+), 28 deletions(-)

diff --git a/src/evdev.c b/src/evdev.c
index 30f809b..4eebced 100644
--- a/src/evdev.c
+++ b/src/evdev.c
@@ -687,28 +687,37 @@ EvdevProcessTouch(InputInfoPtr pInfo)
 {
     EvdevPtr pEvdev = pInfo->private;
     int type;
+    int slot = pEvdev->cur_slot;
 
-    if (pEvdev->cur_slot < 0 || !pEvdev->mt_mask)
+    if (slot < 0 || !pEvdev->mt_mask)
         return;
 
-    /* If the ABS_MT_SLOT is the first event we get after EV_SYN, skip this */
-    if (pEvdev->slot_state == SLOTSTATE_EMPTY)
+    if (!pEvdev->slots[slot].dirty)
         return;
 
-    if (pEvdev->slot_state == SLOTSTATE_CLOSE)
-        type = XI_TouchEnd;
-    else if (pEvdev->slot_state == SLOTSTATE_OPEN)
-        type = XI_TouchBegin;
-    else
-        type = XI_TouchUpdate;
-
+    switch(pEvdev->slots[slot].state)
+    {
+        case SLOTSTATE_EMPTY:
+            return;
+        case SLOTSTATE_CLOSE:
+            type = XI_TouchEnd;
+            pEvdev->slots[slot].state = SLOTSTATE_EMPTY;
+            break;
+        case SLOTSTATE_OPEN:
+            type = XI_TouchBegin;
+            pEvdev->slots[slot].state = SLOTSTATE_UPDATE;
+            break;
+        default:
+            type = XI_TouchUpdate;
+            break;
+    }
 
     EvdevSwapAbsValuators(pEvdev, pEvdev->mt_mask);
     EvdevApplyCalibration(pEvdev, pEvdev->mt_mask);
 
     EvdevQueueTouchEvent(pInfo, pEvdev->cur_slot, pEvdev->mt_mask, type);
 
-    pEvdev->slot_state = SLOTSTATE_EMPTY;
+    pEvdev->slots[slot].dirty = 0;
 
     valuator_mask_zero(pEvdev->mt_mask);
 }
@@ -751,29 +760,28 @@ EvdevProcessTouchEvent(InputInfoPtr pInfo, struct input_event *ev)
     } else
     {
         int slot_index = last_mt_vals_slot(pEvdev);
+        if (slot_index < 0) {
+                    LogMessageVerbSigSafe(X_WARNING, 0,
+                                          "%s: Invalid slot index %d, touch events may be incorrect.\n",
+                                          pInfo->name,
+                                          slot_index);
+                    return;
+        }
 
-        if (pEvdev->slot_state == SLOTSTATE_EMPTY)
-            pEvdev->slot_state = SLOTSTATE_UPDATE;
+        pEvdev->slots[slot_index].dirty = 1;
         if (ev->code == ABS_MT_TRACKING_ID) {
             if (ev->value >= 0) {
-                pEvdev->slot_state = SLOTSTATE_OPEN;
+                pEvdev->slots[slot_index].state = SLOTSTATE_OPEN;
 
-                if (slot_index >= 0)
-                    valuator_mask_copy(pEvdev->mt_mask,
-                                       pEvdev->last_mt_vals[slot_index]);
-                else
-                    LogMessageVerbSigSafe(X_WARNING, 0,
-                                "%s: Attempted to copy values from out-of-range "
-                                "slot, touch events may be incorrect.\n",
-                                pInfo->name);
-            } else
-                pEvdev->slot_state = SLOTSTATE_CLOSE;
+                valuator_mask_copy(pEvdev->mt_mask,
+                                   pEvdev->last_mt_vals[slot_index]);
+            } else if (pEvdev->slots[slot_index].state != SLOTSTATE_EMPTY)
+                pEvdev->slots[slot_index].state = SLOTSTATE_CLOSE;
         } else {
             map = pEvdev->abs_axis_map[ev->code];
             valuator_mask_set(pEvdev->mt_mask, map, ev->value);
-            if (slot_index >= 0)
-                valuator_mask_set(pEvdev->last_mt_vals[slot_index], map,
-                                  ev->value);
+            valuator_mask_set(pEvdev->last_mt_vals[slot_index], map,
+                              ev->value);
         }
     }
 }
@@ -1041,6 +1049,8 @@ EvdevFreeMasks(EvdevPtr pEvdev)
     int i;
 #endif
 
+    free(pEvdev->slots);
+    pEvdev->slots = NULL;
     valuator_mask_free(&pEvdev->vals);
     valuator_mask_free(&pEvdev->old_vals);
     valuator_mask_free(&pEvdev->prox);
@@ -1320,6 +1330,17 @@ EvdevAddAbsValuatorClass(DeviceIntPtr device, int want_scroll_axes)
             goto out;
         }
 
+        pEvdev->slots = calloc(nslots, sizeof(*pEvdev->slots));
+        if (!pEvdev->slots) {
+            xf86Msg(X_ERROR, "%s: failed to allocate slot state array.\n",
+                    device->name);
+            goto out;
+        }
+        for (i = 0; i < nslots; i++) {
+            pEvdev->slots[i].state = SLOTSTATE_EMPTY;
+            pEvdev->slots[i].dirty = 0;
+        }
+
         pEvdev->last_mt_vals = calloc(nslots, sizeof(ValuatorMask *));
         if (!pEvdev->last_mt_vals) {
             xf86IDrvMsg(pInfo, X_ERROR,
diff --git a/src/evdev.h b/src/evdev.h
index 520d017..2d6b62d 100644
--- a/src/evdev.h
+++ b/src/evdev.h
@@ -167,7 +167,10 @@ typedef struct {
     ValuatorMask *mt_mask;
     ValuatorMask **last_mt_vals;
     int cur_slot;
-    enum SlotState slot_state;
+    struct slot {
+        int dirty;
+        enum SlotState state;
+    } *slots;
 #ifdef MULTITOUCH
     struct mtdev *mtdev;
 #endif
-- 
1.9.3