Commit 56b7f4cf3100cd252a0325973fb9093ce0a629ee
2019-06-08T14:40:27
Fixed bug 4583 - PollAllValues appears to use an incorrect index for all axes above 0x18 Noam Preil In src/joystick/linux/SDL_sysjoystick.c: The ConfigJoystick function's axes detection starts with a for loop using an index i for Linux's axes names. When i gets to ABS_HAT0X, it's set to ABS_HAT3Y and a continue statement appears, to skip the hats. This makes sense, as SDL handles hats separately from axes. However, in PollAllValues, *two* indices are used: a and b. Both start out the same, and remain so until the hats are reached. At that point, a becomes identical to the i from ConfigJoystick's loop, but b is equal to a - (ABS_HAT3Y - ABS_HAT0X), or a - 8. While all the joystick->hwdata->abs_* structures in ConfigJoystick used i - which would here be a - as both the index and the ioctl argument, PollAllValues uses b for the structure index and a as the ioctl argument. It would appear, however, that no joystick HAS such axes, and that the b index is entirely unnecessary. I tested three separate joysticks, and while that was far from a complete listing, I was unable to find a joystick with an axis above 0x08.
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diff --git a/src/joystick/linux/SDL_sysjoystick.c b/src/joystick/linux/SDL_sysjoystick.c
index fd26415..0309f8c 100644
--- a/src/joystick/linux/SDL_sysjoystick.c
+++ b/src/joystick/linux/SDL_sysjoystick.c
@@ -818,36 +818,26 @@ static SDL_INLINE void
PollAllValues(SDL_Joystick * joystick)
{
struct input_absinfo absinfo;
- int a, b = 0;
+ int i;
/* Poll all axis */
- for (a = ABS_X; b < ABS_MAX; a++) {
- switch (a) {
- case ABS_HAT0X:
- case ABS_HAT0Y:
- case ABS_HAT1X:
- case ABS_HAT1Y:
- case ABS_HAT2X:
- case ABS_HAT2Y:
- case ABS_HAT3X:
- case ABS_HAT3Y:
- /* ingore hats */
- break;
- default:
- if (joystick->hwdata->abs_correct[b].used) {
- if (ioctl(joystick->hwdata->fd, EVIOCGABS(a), &absinfo) >= 0) {
- absinfo.value = AxisCorrect(joystick, b, absinfo.value);
+ for (i = ABS_X; i < ABS_MAX; i++) {
+ if (i == ABS_HAT0X) {
+ i = ABS_HAT3Y;
+ continue;
+ }
+ if (joystick->hwdata->abs_correct[i].used) {
+ if (ioctl(joystick->hwdata->fd, EVIOCGABS(i), &absinfo) >= 0) {
+ absinfo.value = AxisCorrect(joystick, i, absinfo.value);
#ifdef DEBUG_INPUT_EVENTS
- printf("Joystick : Re-read Axis %d (%d) val= %d\n",
- joystick->hwdata->abs_map[b], a, absinfo.value);
+ printf("Joystick : Re-read Axis %d (%d) val= %d\n",
+ joystick->hwdata->abs_map[i], i, absinfo.value);
#endif
- SDL_PrivateJoystickAxis(joystick,
- joystick->hwdata->abs_map[b],
- absinfo.value);
- }
+ SDL_PrivateJoystickAxis(joystick,
+ joystick->hwdata->abs_map[i],
+ absinfo.value);
}
- b++;
}
}
}