linux: Pass evdev properties when guessing device type

In newer kernels, devices that can be positively identified as a particular device type (for example accelerometers) get a property bit set. Plumb this information through into the function, but don't use it for anything just yet. Signed-off-by: Simon McVittie <smcv@collabora.com>
1bsyl · Jun 16, 2023 · 0d5aa70 · 0d5aa70
1 parent a4ce721
commit 0d5aa70
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Showing 5 changed files with 26 additions and 6 deletions.
diff --git a/src/core/linux/SDL_evdev_capabilities.c b/src/core/linux/SDL_evdev_capabilities.c
@@ -37,7 +37,8 @@
 #endif
 
 extern int
-SDL_EVDEV_GuessDeviceClass(const unsigned long bitmask_ev[NBITS(EV_MAX)],
+SDL_EVDEV_GuessDeviceClass(const unsigned long bitmask_props[NBITS(INPUT_PROP_MAX)],
+                           const unsigned long bitmask_ev[NBITS(EV_MAX)],
                            const unsigned long bitmask_abs[NBITS(ABS_MAX)],
                            const unsigned long bitmask_key[NBITS(KEY_MAX)],
                            const unsigned long bitmask_rel[NBITS(REL_MAX)])

diff --git a/src/core/linux/SDL_evdev_capabilities.h b/src/core/linux/SDL_evdev_capabilities.h
@@ -28,6 +28,10 @@
 
 #include <linux/input.h>
 
+#ifndef INPUT_PROP_MAX
+#define INPUT_PROP_MAX 0x1f
+#endif
+
 /* A device can be any combination of these classes */
 typedef enum
 {
@@ -48,7 +52,8 @@ typedef enum
 #define EVDEV_LONG(x)        ((x) / BITS_PER_LONG)
 #define test_bit(bit, array) ((array[EVDEV_LONG(bit)] >> EVDEV_OFF(bit)) & 1)
 
-extern int SDL_EVDEV_GuessDeviceClass(const unsigned long bitmask_ev[NBITS(EV_MAX)],
+extern int SDL_EVDEV_GuessDeviceClass(const unsigned long bitmask_props[NBITS(INPUT_PROP_MAX)],
+                                      const unsigned long bitmask_ev[NBITS(EV_MAX)],
                                       const unsigned long bitmask_abs[NBITS(ABS_MAX)],
                                       const unsigned long bitmask_key[NBITS(KEY_MAX)],
                                       const unsigned long bitmask_rel[NBITS(REL_MAX)]);

diff --git a/src/core/linux/SDL_udev.c b/src/core/linux/SDL_udev.c
@@ -362,6 +362,7 @@ static void get_caps(struct udev_device *dev, struct udev_device *pdev, const ch
 static int guess_device_class(struct udev_device *dev)
 {
     struct udev_device *pdev;
+    unsigned long bitmask_props[NBITS(INPUT_PROP_MAX)];
     unsigned long bitmask_ev[NBITS(EV_MAX)];
     unsigned long bitmask_abs[NBITS(ABS_MAX)];
     unsigned long bitmask_key[NBITS(KEY_MAX)];
@@ -377,12 +378,14 @@ static int guess_device_class(struct udev_device *dev)
         return 0;
     }
 
+    get_caps(dev, pdev, "properties", bitmask_props, SDL_arraysize(bitmask_props));
     get_caps(dev, pdev, "capabilities/ev", bitmask_ev, SDL_arraysize(bitmask_ev));
     get_caps(dev, pdev, "capabilities/abs", bitmask_abs, SDL_arraysize(bitmask_abs));
     get_caps(dev, pdev, "capabilities/rel", bitmask_rel, SDL_arraysize(bitmask_rel));
     get_caps(dev, pdev, "capabilities/key", bitmask_key, SDL_arraysize(bitmask_key));
 
-    return SDL_EVDEV_GuessDeviceClass(&bitmask_ev[0],
+    return SDL_EVDEV_GuessDeviceClass(&bitmask_props[0],
+                                      &bitmask_ev[0],
                                       &bitmask_abs[0],
                                       &bitmask_key[0],
                                       &bitmask_rel[0]);

diff --git a/src/joystick/linux/SDL_sysjoystick.c b/src/joystick/linux/SDL_sysjoystick.c
@@ -204,6 +204,7 @@ static SDL_bool IsVirtualJoystick(Uint16 vendor, Uint16 product, Uint16 version,
 
 static int GuessIsJoystick(int fd)
 {
+    unsigned long propbit[NBITS(INPUT_PROP_MAX)] = { 0 };
     unsigned long evbit[NBITS(EV_MAX)] = { 0 };
     unsigned long keybit[NBITS(KEY_MAX)] = { 0 };
     unsigned long absbit[NBITS(ABS_MAX)] = { 0 };
@@ -217,7 +218,11 @@ static int GuessIsJoystick(int fd)
         return 0;
     }
 
-    devclass = SDL_EVDEV_GuessDeviceClass(evbit, absbit, keybit, relbit);
+    /* This is a newer feature, so it's allowed to fail - if so, then the
+     * device just doesn't have any properties. */
+    (void) ioctl(fd, EVIOCGPROP(sizeof(propbit)), propbit);
+
+    devclass = SDL_EVDEV_GuessDeviceClass(propbit, evbit, absbit, keybit, relbit);
 
     if (devclass & SDL_UDEV_DEVICE_JOYSTICK) {
         return 1;

diff --git a/test/testevdev.c b/test/testevdev.c
@@ -1794,6 +1794,7 @@ run_test(void)
         int actual;
         struct
         {
+            unsigned long props[NBITS(INPUT_PROP_MAX)];
             unsigned long ev[NBITS(EV_MAX)];
             unsigned long abs[NBITS(ABS_MAX)];
             unsigned long keys[NBITS(KEY_MAX)];
@@ -1803,11 +1804,16 @@ run_test(void)
         printf("%s...\n", t->name);
 
         memset(&caps, '\0', sizeof(caps));
+        memcpy(caps.props, t->props, sizeof(t->props));
         memcpy(caps.ev, t->ev, sizeof(t->ev));
         memcpy(caps.keys, t->keys, sizeof(t->keys));
         memcpy(caps.abs, t->abs, sizeof(t->abs));
         memcpy(caps.rel, t->rel, sizeof(t->rel));
 
+        for (j = 0; j < SDL_arraysize(caps.props); j++) {
+            caps.props[j] = SwapLongLE(caps.props[j]);
+        }
+
         for (j = 0; j < SDL_arraysize(caps.ev); j++) {
             caps.ev[j] = SwapLongLE(caps.ev[j]);
         }
@@ -1824,8 +1830,8 @@ run_test(void)
             caps.rel[j] = SwapLongLE(caps.rel[j]);
         }
 
-        actual = SDL_EVDEV_GuessDeviceClass(caps.ev, caps.abs, caps.keys,
-                                            caps.rel);
+        actual = SDL_EVDEV_GuessDeviceClass(caps.props, caps.ev, caps.abs,
+                                            caps.keys, caps.rel);
 
         if (actual == t->expected) {
             printf("\tOK\n");