Mapping issues NVIDIA Controller v01.03

[davyhollevoet]

I was experiencing some issues while mapping my "NVIDIA Corporation NVIDIA Controller v01.03" gamepad, connected over USB. It seems to me that mapping other controllers might give the same problems, but I can't check that.

With some work and the patches (against d452411) listed below, I did manage to get the following mapping:
03000000550900001072000011010000,NVIDIA Corporation NVIDIA Controller v01.03,a:b0,b:b1,x:b2,y:b3,start:b7,leftstick:b8,rightstick:b9,leftshoulder:b4,rightshoulder:b5,dpup:h0.1,dpleft:h0.8,dpdown:h0.4,dpright:h0.2,leftx:a0,lefty:a1,rightx:a2,righty:a5,lefttrigger:a10,righttrigger:a9,platform:Linux

• Unable to register movement of "Right Stick Up", "Left Trigger" and "Right Trigger". I believe that this is due to the gap in ABS code: ABS_Z is 2 and ABS_RZ is 5, with nothing in between. A few empty slots later, there is ABS_GAS and ABS_BRAKE at 9 and 10. The following patch fixes the confusion between index and value in abs_map.

diff --git a/src/input/evdev.c b/src/input/evdev.c
index 5f78716..fb2903f 100644
--- a/src/input/evdev.c
+++ b/src/input/evdev.c
@@ -403,7 +403,7 @@ static bool evdev_handle_mapping_event(struct input_event *ev, struct input_devi
       } else if (ev->value < parms.avg - parms.range/2) {
         *currentAbs = dev->abs_map[ev->code];
         *currentReverse = true;
-      } else if (ev->code == *currentAbs)
+      } else if (dev->abs_map[ev->code] == *currentAbs)
         return false;
     } else if (currentHat != NULL) {
       if (hat_index >= 0 && hat_index < 4) {
@@ -532,13 +532,12 @@ void evdev_create(const char* device, struct mapping* mappings, bool verbose) {
       devices[dev].key_map[i - BTN_MISC] = nbuttons++;
   }
 
-  int naxes = 0;
   for (int i = 0; i < ABS_MAX; ++i) {
     /* Skip hats */
     if (i == ABS_HAT0X)
       i = ABS_HAT3Y;
     else if (libevdev_has_event_code(devices[dev].dev, EV_ABS, i))
-      devices[dev].abs_map[i] = naxes++;
+      devices[dev].abs_map[i] = i;
   }
 
   devices[dev].controllerId = -1;

• The "D-Pad Up" and "D-Pad Down" were being mapped to dpup:h0.9 and dpdown:h0.12 instead of dpup:h0.1 and dpdown:h0.4. Resetting hats_state after deciding each hat button fixes that:

diff --git a/src/input/evdev.c b/src/input/evdev.c
index e04bf9c..5f78716 100644
--- a/src/input/evdev.c
+++ b/src/input/evdev.c
@@ -409,6 +409,9 @@ static bool evdev_handle_mapping_event(struct input_event *ev, struct input_devi
       if (hat_index >= 0 && hat_index < 4) {
         *currentHat = hat_index;
         *currentHatDir = hat_constants[dev->hats_state[hat_index][1] + 1][dev->hats_state[hat_index][0] + 1];
+        //reset the states for the next hat button
+        dev->hats_state[hat_index][1] = 0;
+        dev->hats_state[hat_index][0] = 0;
         return false;
       }
     }

• In the final mapping output, the name is blank, which makes the mapping reader skip a:b0 (strtok does that for empty fields). The cause of the blank name is an off-by-one(?) overflow due to the wrong size for strncpy.

diff --git a/src/input/evdev.c b/src/input/evdev.c
index fb2903f..e29c958 100644
--- a/src/input/evdev.c
+++ b/src/input/evdev.c
@@ -636,7 +636,7 @@ void evdev_map(char* device) {
   
   struct mapping map;
   strncpy(map.name, libevdev_get_name(evdev), sizeof(map.name));
-  strncpy(map.guid, str_guid, sizeof(map.name));
+  strncpy(map.guid, str_guid, sizeof(map.guid));
 
   libevdev_free(evdev);
   close(fd);

One remaining issue is that, to map "Left Trigger" and "Right Trigger", one should only tap the triggers only very shortly: the detection code does not take into account that the value starts at 0 instead of halfway.

Finally, more as FYI, the "Back" and "Home" buttons on the gamepad don't do anything during the mapping because their codes (KEY_BACK, KEY_HOMEPAGE) are not within the correct ranges. Since I wanted to get the same behavior as with the Nvidia GameStream app, I used the patch below. This prolly interferes with keyboard input, but is good enough for me personally.

diff --git a/src/input/evdev.c b/src/input/evdev.c
index 7fc1181..e04bf9c 100644
--- a/src/input/evdev.c
+++ b/src/input/evdev.c
@@ -244,6 +244,14 @@ static bool evdev_handle_event(struct input_event *ev, struct input_device *dev)
       case BTN_RIGHT:
         mouseCode = BUTTON_RIGHT;
         break;
+      case KEY_BACK:
+        gamepadModified = true;
+        gamepadCode = BACK_FLAG;
+        break;
+      case KEY_HOMEPAGE:
+        gamepadModified = true;
+        gamepadCode = SPECIAL_FLAG;
+        break;
       default:
         gamepadModified = true;
         if (dev->map == NULL)