Fixed bug 4789 - Linux accelerometers no longer available as joysticks

Daniel Drake

A long time ago, it was possible to play neverball on Linux using the accelerometer found in HP laptops.

The kernel exposes the accelerometer as a joystick (/dev/input/jsX) as well as an evdev device (/dev/input/eventX). I guess it worked fine when SDL was using the js interface, but then stopped working here: http://hg.libsdl.org/SDL/rev/fdaeea9e7567

Looking at current code which uses udev to discover joysticks, it looks for the udev tag ID_INPUT_JOYSTICK.

However udev's internal input_id logic specifically tags accelerometers as ID_INPUT_ACCELEROMETER and nothing else.

This looks like a good fit for SDL_HINT_ACCELEROMETER_AS_JOYSTICK.
This commit is contained in:
Sam Lantinga 2019-09-06 08:42:54 -07:00
parent 8a394209c4
commit aaec90e5c5

View File

@ -34,6 +34,7 @@
#include "SDL_assert.h"
#include "SDL_loadso.h"
#include "SDL_timer.h"
#include "SDL_hints.h"
#include "../unix/SDL_poll.h"
static const char *SDL_UDEV_LIBS[] = { "libudev.so.1", "libudev.so.0" };
@ -420,6 +421,12 @@ device_event(SDL_UDEV_deviceevent type, struct udev_device *dev)
if (val != NULL && SDL_strcmp(val, "1") == 0 ) {
devclass |= SDL_UDEV_DEVICE_JOYSTICK;
}
val = _this->syms.udev_device_get_property_value(dev, "ID_INPUT_ACCELEROMETER");
if (SDL_GetHintBoolean(SDL_HINT_ACCELEROMETER_AS_JOYSTICK, SDL_TRUE) &&
val != NULL && SDL_strcmp(val, "1") == 0 ) {
devclass |= SDL_UDEV_DEVICE_JOYSTICK;
}
val = _this->syms.udev_device_get_property_value(dev, "ID_INPUT_MOUSE");
if (val != NULL && SDL_strcmp(val, "1") == 0 ) {