linux: Distinguish between "device with keys" and a full keyboard

udev distinguishes between ID_INPUT_KEY, a device with any keyboard keys
at all (including for example USB numeric keypads, Bluetooth headsets
with volume control buttons, and some game controllers; and
ID_INPUT_KEYBOARD, a reasonably fully-featured keyboard that you could
use for general-purpose text entry. If we do the same here, then it's
useful input to our heuristics for identifying devices: for example,
a device with ID_INPUT_KEY could reasonably be a gamepad, but a device
with ID_INPUT_KEYBOARD certainly isn't.

Resolves: https://github.com/libsdl-org/SDL/issues/7827
Signed-off-by: Simon McVittie <smcv@collabora.com>

src/core/linux/SDL_evdev.c

@@ -245,7 +245,7 @@ static void SDL_EVDEV_udev_callback(SDL_UDEV_deviceevent udev_event, int udev_cl
 
     switch (udev_event) {
     case SDL_UDEV_DEVICEADDED:
-        if (!(udev_class & (SDL_UDEV_DEVICE_MOUSE | SDL_UDEV_DEVICE_KEYBOARD | SDL_UDEV_DEVICE_TOUCHSCREEN | SDL_UDEV_DEVICE_TOUCHPAD))) {
+        if (!(udev_class & (SDL_UDEV_DEVICE_MOUSE | SDL_UDEV_DEVICE_HAS_KEYS | SDL_UDEV_DEVICE_TOUCHSCREEN | SDL_UDEV_DEVICE_TOUCHPAD))) {
             return;
         }
 

src/core/linux/SDL_evdev_capabilities.c

@@ -131,14 +131,15 @@ SDL_EVDEV_GuessDeviceClass(const unsigned long bitmask_ev[NBITS(EV_MAX)],
         }
 
         if (found > 0) {
-            devclass |= SDL_UDEV_DEVICE_KEYBOARD; /* ID_INPUT_KEY */
+            devclass |= SDL_UDEV_DEVICE_HAS_KEYS; /* ID_INPUT_KEY */
         }
     }
 
-    /* the first 32 bits are ESC, numbers, and Q to D; if we have any of
-     * those, consider it a keyboard device; do not test KEY_RESERVED, though */
+    /* the first 32 bits are ESC, numbers, and Q to D, so if we have all of
+     * those, consider it to be a fully-featured keyboard;
+     * do not test KEY_RESERVED, though */
     keyboard_mask = 0xFFFFFFFE;
-    if ((bitmask_key[0] & keyboard_mask) != 0) {
+    if ((bitmask_key[0] & keyboard_mask) == keyboard_mask) {
         devclass |= SDL_UDEV_DEVICE_KEYBOARD; /* ID_INPUT_KEYBOARD */
     }
 

src/core/linux/SDL_evdev_capabilities.h

@@ -38,7 +38,8 @@ typedef enum
     SDL_UDEV_DEVICE_SOUND = 0x0008,
     SDL_UDEV_DEVICE_TOUCHSCREEN = 0x0010,
     SDL_UDEV_DEVICE_ACCELEROMETER = 0x0020,
-    SDL_UDEV_DEVICE_TOUCHPAD = 0x0040
+    SDL_UDEV_DEVICE_TOUCHPAD = 0x0040,
+    SDL_UDEV_DEVICE_HAS_KEYS = 0x0080,
 } SDL_UDEV_deviceclass;
 
 #define BITS_PER_LONG        (sizeof(unsigned long) * 8)

src/core/linux/SDL_udev.c

@@ -435,6 +435,11 @@ static void device_event(SDL_UDEV_deviceevent type, struct udev_device *dev)
            Ref: http://cgit.freedesktop.org/systemd/systemd/tree/src/udev/udev-builtin-input_id.c#n183
         */
         val = _this->syms.udev_device_get_property_value(dev, "ID_INPUT_KEY");
+        if (val != NULL && SDL_strcmp(val, "1") == 0) {
+            devclass |= SDL_UDEV_DEVICE_HAS_KEYS;
+        }
+
+        val = _this->syms.udev_device_get_property_value(dev, "ID_INPUT_KEYBOARD");
         if (val != NULL && SDL_strcmp(val, "1") == 0) {
             devclass |= SDL_UDEV_DEVICE_KEYBOARD;
         }
@@ -448,7 +453,7 @@ static void device_event(SDL_UDEV_deviceevent type, struct udev_device *dev)
                 } else if (SDL_strcmp(val, "mouse") == 0) {
                     devclass = SDL_UDEV_DEVICE_MOUSE;
                 } else if (SDL_strcmp(val, "kbd") == 0) {
-                    devclass = SDL_UDEV_DEVICE_KEYBOARD;
+                    devclass = SDL_UDEV_DEVICE_HAS_KEYS | SDL_UDEV_DEVICE_KEYBOARD;
                 } else {
                     return;
                 }

test/testevdev.c

@@ -48,6 +48,7 @@ static const struct
     }
     CLS(MOUSE),
     CLS(KEYBOARD),
+    CLS(HAS_KEYS),
     CLS(JOYSTICK),
     CLS(SOUND),
     CLS(TOUCHSCREEN),
@@ -351,7 +352,7 @@ static const GuessTest guess_tests[] =
       .vendor_id = 0x045e,
       .product_id = 0x0b22,
       .version = 0x0517,
-      .expected = SDL_UDEV_DEVICE_JOYSTICK | SDL_UDEV_DEVICE_KEYBOARD,
+      .expected = SDL_UDEV_DEVICE_JOYSTICK | SDL_UDEV_DEVICE_HAS_KEYS,
       /* SYN, KEY, ABS, FF */
       .ev = { 0x0b, 0x00, 0x20 },
       /* Android-style mapping:
@@ -638,7 +639,8 @@ static const GuessTest guess_tests[] =
       .bus_type = 0x0003,
       .vendor_id = 0x28de,
       .product_id = 0x1142,
-      .expected = (SDL_UDEV_DEVICE_KEYBOARD
+      .expected = (SDL_UDEV_DEVICE_HAS_KEYS
+                   | SDL_UDEV_DEVICE_KEYBOARD
                    | SDL_UDEV_DEVICE_MOUSE),
       /* SYN, KEY, REL, MSC, LED, REP */
       .ev = { 0x17, 0x00, 0x12 },
@@ -1087,7 +1089,7 @@ static const GuessTest guess_tests[] =
       .vendor_id = 0x045e,
       .product_id = 0x02e0,
       .version = 0x0903,
-      .expected = SDL_UDEV_DEVICE_JOYSTICK | SDL_UDEV_DEVICE_KEYBOARD,
+      .expected = SDL_UDEV_DEVICE_JOYSTICK | SDL_UDEV_DEVICE_HAS_KEYS,
       /* SYN, KEY, ABS, MSC, FF */
       .ev = { 0x1b, 0x00, 0x20 },
       /* X, Y, Z, RX, RY, RZ, HAT0X, HAT0Y */
@@ -1132,7 +1134,7 @@ static const GuessTest guess_tests[] =
       .vendor_id = 0x18d1,
       .product_id = 0x9400,
       .version = 0x0100,
-      .expected = SDL_UDEV_DEVICE_JOYSTICK | SDL_UDEV_DEVICE_KEYBOARD,
+      .expected = SDL_UDEV_DEVICE_JOYSTICK | SDL_UDEV_DEVICE_HAS_KEYS,
       .ev = { 0x0b },
       /* XYZ, RZ, gas, brake, hat0 */
       .abs = { 0x27, 0x06, 0x03 },
@@ -1166,7 +1168,7 @@ static const GuessTest guess_tests[] =
       .vendor_id = 0x045e,
       .product_id = 0x0b12,
       .version = 0x050f,
-      .expected = SDL_UDEV_DEVICE_JOYSTICK | SDL_UDEV_DEVICE_KEYBOARD,
+      .expected = SDL_UDEV_DEVICE_JOYSTICK | SDL_UDEV_DEVICE_HAS_KEYS,
       .ev = { 0x0b },
       /* X, Y, Z, RX, RY, RZ, hat 0 */
       .abs = { 0x3f, 0x00, 0x03 },
@@ -1189,7 +1191,7 @@ static const GuessTest guess_tests[] =
       .vendor_id = 0x045e,
       .product_id = 0x0b13,
       .version = 0x0515,
-      .expected = SDL_UDEV_DEVICE_JOYSTICK | SDL_UDEV_DEVICE_KEYBOARD,
+      .expected = SDL_UDEV_DEVICE_JOYSTICK | SDL_UDEV_DEVICE_HAS_KEYS,
       .ev = { 0x0b },
       /* XYZ, RZ, gas, brake, hat0 */
       .abs = { 0x27, 0x06, 0x03 },
@@ -1214,8 +1216,8 @@ static const GuessTest guess_tests[] =
       /* This one is a bit weird because some of the buttons are mapped
        * to the arrow, page up and page down keys, so it's a joystick
        * with a subset of a keyboard attached. */
-      /* TODO: Should this be JOYSTICK, or even JOYSTICK|KEYBOARD? */
-      .expected = SDL_UDEV_DEVICE_KEYBOARD,
+      /* TODO: Should this be JOYSTICK, or even JOYSTICK|HAS_KEYS? */
+      .expected = SDL_UDEV_DEVICE_HAS_KEYS,
       /* SYN, KEY, FF */
       .ev = { 0x03, 0x00, 0x20 },
       .keys = {
@@ -1296,9 +1298,9 @@ static const GuessTest guess_tests[] =
     {
       .name = "Wiimote - Classic Controller",
       .eviocgname = "Nintendo Wii Remote Classic Controller",
-      /* TODO: Should this be JOYSTICK, or maybe JOYSTICK|KEYBOARD?
+      /* TODO: Should this be JOYSTICK, or maybe JOYSTICK|HAS_KEYS?
        * It's unusual in the same ways as the Wiimote */
-      .expected = SDL_UDEV_DEVICE_KEYBOARD,
+      .expected = SDL_UDEV_DEVICE_HAS_KEYS,
       /* SYN, KEY, ABS */
       .ev = { 0x0b },
       /* Hat 1-3 X and Y */
@@ -1422,8 +1424,7 @@ static const GuessTest guess_tests[] =
       .vendor_id = 0x17aa,
       .product_id = 0x5054,
       .version = 0x4101,
-      /* SDL treats this as a keyboard because it has a power button */
-      .expected = SDL_UDEV_DEVICE_KEYBOARD,
+      .expected = SDL_UDEV_DEVICE_HAS_KEYS,
       /* SYN, KEY, MSC, SW */
       .ev = { 0x33 },
       .keys = {
@@ -1446,7 +1447,7 @@ static const GuessTest guess_tests[] =
       .vendor_id = 0x17aa,
       .product_id = 0x5054,
       .version = 0x4101,
-      .expected = SDL_UDEV_DEVICE_KEYBOARD,
+      .expected = SDL_UDEV_DEVICE_HAS_KEYS,
       /* SYN, KEY, MSC, SW */
       .ev = { 0x33 },
       .keys = {
@@ -1507,7 +1508,7 @@ static const GuessTest guess_tests[] =
       .vendor_id = 0x0001,
       .product_id = 0x0001,
       .version = 0xab54,
-      .expected = SDL_UDEV_DEVICE_KEYBOARD,
+      .expected = SDL_UDEV_DEVICE_HAS_KEYS | SDL_UDEV_DEVICE_KEYBOARD,
       /* SYN, KEY, MSC, LED, REP */
       .ev = { 0x13, 0x00, 0x12 },
       .keys = {
@@ -1524,8 +1525,7 @@ static const GuessTest guess_tests[] =
       .vendor_id = 0x0000,
       .product_id = 0x0003,
       .version = 0x0000,
-      /* SDL treats KEY_SLEEP as indicating a keyboard */
-      .expected = SDL_UDEV_DEVICE_KEYBOARD,
+      .expected = SDL_UDEV_DEVICE_HAS_KEYS,
       /* SYN, KEY */
       .ev = { 0x03 },
       .keys = {
@@ -1553,8 +1553,7 @@ static const GuessTest guess_tests[] =
       .vendor_id = 0x0000,
       .product_id = 0x0001,
       .version = 0x0000,
-      /* SDL treats KEY_POWER as indicating a keyboard */
-      .expected = SDL_UDEV_DEVICE_KEYBOARD,
+      .expected = SDL_UDEV_DEVICE_HAS_KEYS,
       /* SYN, KEY */
       .ev = { 0x03 },
       .keys = {
@@ -1570,8 +1569,7 @@ static const GuessTest guess_tests[] =
       .vendor_id = 0x0000,
       .product_id = 0x0006,
       .version = 0x0000,
-      /* SDL treats brightness control, etc. as keyboard keys */
-      .expected = SDL_UDEV_DEVICE_KEYBOARD,
+      .expected = SDL_UDEV_DEVICE_HAS_KEYS,
       /* SYN, KEY */
       .ev = { 0x03 },
       .keys = {
@@ -1591,7 +1589,7 @@ static const GuessTest guess_tests[] =
       .vendor_id = 0x04f2,
       .product_id = 0xb604,
       .version = 0x0027,
-      .expected = SDL_UDEV_DEVICE_KEYBOARD,
+      .expected = SDL_UDEV_DEVICE_HAS_KEYS,
       /* SYN, KEY */
       .ev = { 0x03 },
       .keys = {
@@ -1608,7 +1606,7 @@ static const GuessTest guess_tests[] =
       .vendor_id = 0x17aa,
       .product_id = 0x5054,
       .version = 0x4101,
-      .expected = SDL_UDEV_DEVICE_KEYBOARD,
+      .expected = SDL_UDEV_DEVICE_HAS_KEYS,
       /* SYN, KEY */
       .ev = { 0x03 },
       .keys = {
@@ -1632,7 +1630,7 @@ static const GuessTest guess_tests[] =
       .bus_type = 0x0003,
       .vendor_id = 0x17ef,
       .product_id = 0x6009,
-      .expected = SDL_UDEV_DEVICE_KEYBOARD,
+      .expected = SDL_UDEV_DEVICE_HAS_KEYS | SDL_UDEV_DEVICE_KEYBOARD,
       /* SYN, KEY, MSC, LED, REP */
       .ev = { 0x13, 0x00, 0x12 },
       .keys = {
@@ -1656,7 +1654,7 @@ static const GuessTest guess_tests[] =
       /* For some reason the special keys like mute and wlan toggle
        * show up here instead of, or in addition to, as part of
        * the keyboard - so both udev and SDL report this as having keys too. */
-      .expected = SDL_UDEV_DEVICE_MOUSE | SDL_UDEV_DEVICE_KEYBOARD,
+      .expected = SDL_UDEV_DEVICE_MOUSE | SDL_UDEV_DEVICE_HAS_KEYS,
       /* SYN, KEY, REL, MSC, LED */
       .ev = { 0x17, 0x00, 0x02 },
       /* X, Y */