update SDL soruce to 2.0.14

Edward Rudd

2021-06-15 dec7875a6e23212021e4d9080330a42832dfe02a

 source/src/joystick/linux/SDL_sysjoystick.c

@@ -32,13 +32,17 @@
#include <errno.h>              /* errno, strerror */
#include <fcntl.h>
#include <limits.h>             /* For the definition of PATH_MAX */
#ifdef HAVE_INOTIFY
#include <sys/inotify.h>
#endif
#include <sys/ioctl.h>
#include <unistd.h>
#include <dirent.h>
#include <linux/joystick.h>

#include "SDL_assert.h"
#include "SDL_hints.h"
#include "SDL_joystick.h"
#include "SDL_log.h"
#include "SDL_endian.h"
#include "SDL_timer.h"
#include "../../events/SDL_events_c.h"
@@ -52,13 +56,49 @@
#ifndef SYN_DROPPED
#define SYN_DROPPED 3
#endif
#ifndef BTN_SOUTH
#define BTN_SOUTH       0x130
#endif
#ifndef BTN_EAST
#define BTN_EAST        0x131
#endif
#ifndef BTN_NORTH
#define BTN_NORTH       0x133
#endif
#ifndef BTN_WEST
#define BTN_WEST        0x134
#endif
#ifndef BTN_DPAD_UP
#define BTN_DPAD_UP     0x220
#endif
#ifndef BTN_DPAD_DOWN
#define BTN_DPAD_DOWN   0x221
#endif
#ifndef BTN_DPAD_LEFT
#define BTN_DPAD_LEFT   0x222
#endif
#ifndef BTN_DPAD_RIGHT
#define BTN_DPAD_RIGHT  0x223
#endif

#include "../../core/linux/SDL_evdev_capabilities.h"
#include "../../core/linux/SDL_udev.h"

#if 0
#define DEBUG_INPUT_EVENTS 1
#endif

typedef enum
{
    ENUMERATION_UNSET,
    ENUMERATION_LIBUDEV,
    ENUMERATION_FALLBACK
} EnumerationMethod;

static EnumerationMethod enumeration_method = ENUMERATION_UNSET;

static int MaybeAddDevice(const char *path);
#if SDL_USE_LIBUDEV
static int MaybeRemoveDevice(const char *path);
#endif /* SDL_USE_LIBUDEV */

/* A linked list of available joysticks */
typedef struct SDL_joylist_item
@@ -78,29 +118,10 @@
static SDL_joylist_item *SDL_joylist = NULL;
static SDL_joylist_item *SDL_joylist_tail = NULL;
static int numjoysticks = 0;
static int inotify_fd = -1;

#if !SDL_USE_LIBUDEV
static Uint32 last_joy_detect_time;
static time_t last_input_dir_mtime;
#endif

#define test_bit(nr, addr) \
    (((1UL << ((nr) % (sizeof(long) * 8))) & ((addr)[(nr) / (sizeof(long) * 8)])) != 0)
#define NBITS(x) ((((x)-1)/(sizeof(long) * 8))+1)

static int
PrefixMatch(const char *a, const char *b)
{
    int matchlen = 0;
    while (*a && *b) {
        if (*a++ == *b++) {
            ++matchlen;
        } else {
            break;
        }
    }
    return matchlen;
}

static void
FixupDeviceInfoForMapping(int fd, struct input_id *inpid)
@@ -118,58 +139,75 @@
    }
}

#ifdef SDL_JOYSTICK_HIDAPI
static SDL_bool
IsVirtualJoystick(Uint16 vendor, Uint16 product, Uint16 version, const char *name)
{
    if (vendor == USB_VENDOR_MICROSOFT && product == USB_PRODUCT_XBOX_ONE_S && version == 0 &&
        SDL_strcmp(name, "Xbox One S Controller") == 0) {
        /* This is the virtual device created by the xow driver */
        return SDL_TRUE;
    }
    return SDL_FALSE;
}
#endif /* SDL_JOYSTICK_HIDAPI */

static int
IsJoystick(int fd, char *namebuf, const size_t namebuflen, SDL_JoystickGUID *guid)
GuessIsJoystick(int fd)
{
    struct input_id inpid;
    Uint16 *guid16 = (Uint16 *)guid->data;
    const char *name;
    const char *spot;

#if !SDL_USE_LIBUDEV
    /* When udev is enabled we only get joystick devices here, so there's no need to test them */
    unsigned long evbit[NBITS(EV_MAX)] = { 0 };
    unsigned long keybit[NBITS(KEY_MAX)] = { 0 };
    unsigned long absbit[NBITS(ABS_MAX)] = { 0 };
    unsigned long relbit[NBITS(REL_MAX)] = { 0 };
    int devclass;

    if ((ioctl(fd, EVIOCGBIT(0, sizeof(evbit)), evbit) < 0) ||
        (ioctl(fd, EVIOCGBIT(EV_KEY, sizeof(keybit)), keybit) < 0) ||
        (ioctl(fd, EVIOCGBIT(EV_REL, sizeof(relbit)), relbit) < 0) ||
        (ioctl(fd, EVIOCGBIT(EV_ABS, sizeof(absbit)), absbit) < 0)) {
        return (0);
    }

    if (!(test_bit(EV_KEY, evbit) && test_bit(EV_ABS, evbit) &&
          test_bit(ABS_X, absbit) && test_bit(ABS_Y, absbit))) {
    devclass = SDL_EVDEV_GuessDeviceClass(evbit, absbit, keybit, relbit);

    if (devclass & SDL_UDEV_DEVICE_JOYSTICK) {
        return 1;
    }

    return 0;
}

static int
IsJoystick(int fd, char **name_return, SDL_JoystickGUID *guid)
{
    struct input_id inpid;
    Uint16 *guid16 = (Uint16 *)guid->data;
    char *name;
    char product_string[128];

    /* When udev is enabled we only get joystick devices here, so there's no need to test them */
    if (enumeration_method != ENUMERATION_LIBUDEV && !GuessIsJoystick(fd)) {
        return 0;
    }
#endif

    if (ioctl(fd, EVIOCGID, &inpid) < 0) {
        return 0;
    }

    name = SDL_GetCustomJoystickName(inpid.vendor, inpid.product);
    if (name) {
        SDL_strlcpy(namebuf, name, namebuflen);
    } else {
        if (ioctl(fd, EVIOCGNAME(namebuflen), namebuf) < 0) {
            return 0;
        }
    if (ioctl(fd, EVIOCGNAME(sizeof(product_string)), product_string) < 0) {
        return 0;
    }

        /* Remove duplicate manufacturer in the name */
        for (spot = namebuf + 1; *spot; ++spot) {
            int matchlen = PrefixMatch(namebuf, spot);
            if (matchlen > 0 && spot[matchlen - 1] == ' ') {
                SDL_memmove(namebuf, spot, SDL_strlen(spot)+1);
                break;
            }
        }
    name = SDL_CreateJoystickName(inpid.vendor, inpid.product, NULL, product_string);
    if (!name) {
        return 0;
    }

#ifdef SDL_JOYSTICK_HIDAPI
    if (HIDAPI_IsDevicePresent(inpid.vendor, inpid.product, inpid.version, namebuf)) {
    if (!IsVirtualJoystick(inpid.vendor, inpid.product, inpid.version, name) &&
        HIDAPI_IsDevicePresent(inpid.vendor, inpid.product, inpid.version, name)) {
        /* The HIDAPI driver is taking care of this device */
        SDL_free(name);
        return 0;
    }
#endif
@@ -177,7 +215,7 @@
    FixupDeviceInfoForMapping(fd, &inpid);

#ifdef DEBUG_JOYSTICK
    printf("Joystick: %s, bustype = %d, vendor = 0x%.4x, product = 0x%.4x, version = %d\n", namebuf, inpid.bustype, inpid.vendor, inpid.product, inpid.version);
    printf("Joystick: %s, bustype = %d, vendor = 0x%.4x, product = 0x%.4x, version = %d\n", name, inpid.bustype, inpid.vendor, inpid.product, inpid.version);
#endif

    SDL_memset(guid->data, 0, sizeof(guid->data));
@@ -195,12 +233,14 @@
        *guid16++ = SDL_SwapLE16(inpid.version);
        *guid16++ = 0;
    } else {
        SDL_strlcpy((char*)guid16, namebuf, sizeof(guid->data) - 4);
        SDL_strlcpy((char*)guid16, name, sizeof(guid->data) - 4);
    }

    if (SDL_ShouldIgnoreJoystick(namebuf, *guid)) {
    if (SDL_ShouldIgnoreJoystick(name, *guid)) {
        SDL_free(name);
        return 0;
    }
    *name_return = name;
    return 1;
}

@@ -236,7 +276,7 @@
    struct stat sb;
    int fd = -1;
    int isstick = 0;
    char namebuf[128];
    char *name = NULL;
    SDL_JoystickGUID guid;
    SDL_joylist_item *item;

@@ -264,7 +304,7 @@
    printf("Checking %s\n", path);
#endif

    isstick = IsJoystick(fd, namebuf, sizeof (namebuf), &guid);
    isstick = IsJoystick(fd, &name, &guid);
    close(fd);
    if (!isstick) {
        return -1;
@@ -278,7 +318,7 @@
    SDL_zerop(item);
    item->devnum = sb.st_rdev;
    item->path = SDL_strdup(path);
    item->name = SDL_strdup(namebuf);
    item->name = name;
    item->guid = guid;

    if ((item->path == NULL) || (item->name == NULL)) {
@@ -304,7 +344,6 @@
    return numjoysticks;
}

#if SDL_USE_LIBUDEV
static int
MaybeRemoveDevice(const char *path)
{
@@ -347,7 +386,6 @@

    return -1;
}
#endif

static void
HandlePendingRemovals(void)
@@ -461,12 +499,98 @@
    }
}

static void
LINUX_JoystickDetect(void)
{
#if SDL_USE_LIBUDEV
    SDL_UDEV_Poll();
#ifdef HAVE_INOTIFY
#ifdef HAVE_INOTIFY_INIT1
static int SDL_inotify_init1(void) {
    return inotify_init1(IN_NONBLOCK | IN_CLOEXEC);
}
#else
static int SDL_inotify_init1(void) {
    int fd = inotify_init();
    if (fd  < 0) return -1;
    fcntl(fd, F_SETFL, O_NONBLOCK);
    fcntl(fd, F_SETFD, FD_CLOEXEC);
    return fd;
}
#endif

static int
StrHasPrefix(const char *string, const char *prefix)
{
    return (SDL_strncmp(string, prefix, SDL_strlen(prefix)) == 0);
}

static int
StrIsInteger(const char *string)
{
    const char *p;

    if (*string == '\0') {
        return 0;
    }

    for (p = string; *p != '\0'; p++) {
        if (*p < '0' || *p > '9') {
            return 0;
        }
    }

    return 1;
}

static void
LINUX_InotifyJoystickDetect(void)
{
    union
    {
        struct inotify_event event;
        char storage[4096];
        char enough_for_inotify[sizeof (struct inotify_event) + NAME_MAX + 1];
    } buf;
    ssize_t bytes;
    size_t remain = 0;
    size_t len;

    bytes = read(inotify_fd, &buf, sizeof (buf));

    if (bytes > 0) {
        remain = (size_t) bytes;
    }

    while (remain > 0) {
        if (buf.event.len > 0) {
            if (StrHasPrefix(buf.event.name, "event") &&
                StrIsInteger(buf.event.name + strlen ("event"))) {
                char path[PATH_MAX];

                SDL_snprintf(path, SDL_arraysize(path), "/dev/input/%s", buf.event.name);

                if (buf.event.mask & (IN_CREATE | IN_MOVED_TO | IN_ATTRIB)) {
                    MaybeAddDevice(path);
                }
                else if (buf.event.mask & (IN_DELETE | IN_MOVED_FROM)) {
                    MaybeRemoveDevice(path);
                }
            }
        }

        len = sizeof (struct inotify_event) + buf.event.len;
        remain -= len;

        if (remain != 0) {
            memmove (&buf.storage[0], &buf.storage[len], remain);
        }
    }
}
#endif /* HAVE_INOTIFY */

/* Detect devices by reading /dev/input. In the inotify code path we
 * have to do this the first time, to detect devices that already existed
 * before we started; in the non-inotify code path we do this repeatedly
 * (polling). */
static void
LINUX_FallbackJoystickDetect(void)
{
    const Uint32 SDL_JOY_DETECT_INTERVAL_MS = 3000;  /* Update every 3 seconds */
    Uint32 now = SDL_GetTicks();

@@ -497,7 +621,26 @@

        last_joy_detect_time = now;
    }
}

static void
LINUX_JoystickDetect(void)
{
#if SDL_USE_LIBUDEV
    if (enumeration_method == ENUMERATION_LIBUDEV) {
        SDL_UDEV_Poll();
    }
    else
#endif
#ifdef HAVE_INOTIFY
    if (inotify_fd >= 0 && last_joy_detect_time != 0) {
        LINUX_InotifyJoystickDetect();
    }
    else
#endif
    {
        LINUX_FallbackJoystickDetect();
    }

    HandlePendingRemovals();

@@ -507,6 +650,27 @@
static int
LINUX_JoystickInit(void)
{
#if SDL_USE_LIBUDEV
    if (enumeration_method == ENUMERATION_UNSET) {
        if (SDL_getenv("SDL_JOYSTICK_DISABLE_UDEV") != NULL) {
            SDL_LogDebug(SDL_LOG_CATEGORY_INPUT,
                         "udev disabled by SDL_JOYSTICK_DISABLE_UDEV");
            enumeration_method = ENUMERATION_FALLBACK;
        }
        else if (access("/.flatpak-info", F_OK) == 0
                 || access("/run/pressure-vessel", F_OK) == 0) {
            SDL_LogDebug(SDL_LOG_CATEGORY_INPUT,
                         "Container detected, disabling udev integration");
            enumeration_method = ENUMERATION_FALLBACK;
        }
        else {
            SDL_LogDebug(SDL_LOG_CATEGORY_INPUT,
                         "Using udev for joystick device discovery");
            enumeration_method = ENUMERATION_LIBUDEV;
        }
    }
#endif

    /* First see if the user specified one or more joysticks to use */
    if (SDL_getenv("SDL_JOYSTICK_DEVICE") != NULL) {
        char *envcopy, *envpath, *delim;
@@ -526,27 +690,55 @@
    SDL_InitSteamControllers(SteamControllerConnectedCallback,
                             SteamControllerDisconnectedCallback);

#if SDL_USE_LIBUDEV
    if (SDL_UDEV_Init() < 0) {
        return SDL_SetError("Could not initialize UDEV");
    }

    /* Set up the udev callback */
    if (SDL_UDEV_AddCallback(joystick_udev_callback) < 0) {
        SDL_UDEV_Quit();
        return SDL_SetError("Could not set up joystick <-> udev callback");
    }

    /* Force a scan to build the initial device list */
    SDL_UDEV_Scan();
#else
    /* Force immediate joystick detection */
    /* Force immediate joystick detection if using fallback */
    last_joy_detect_time = 0;
    last_input_dir_mtime = 0;

    /* Report all devices currently present */
    LINUX_JoystickDetect();
#if SDL_USE_LIBUDEV
    if (enumeration_method == ENUMERATION_LIBUDEV) {
        if (SDL_UDEV_Init() < 0) {
            return SDL_SetError("Could not initialize UDEV");
        }

        /* Set up the udev callback */
        if (SDL_UDEV_AddCallback(joystick_udev_callback) < 0) {
            SDL_UDEV_Quit();
            return SDL_SetError("Could not set up joystick <-> udev callback");
        }

        /* Force a scan to build the initial device list */
        SDL_UDEV_Scan();
    }
    else
#endif
    {
#if defined(HAVE_INOTIFY)
        inotify_fd = SDL_inotify_init1();

        if (inotify_fd < 0) {
            SDL_LogWarn(SDL_LOG_CATEGORY_INPUT,
                        "Unable to initialize inotify, falling back to polling: %s",
                        strerror (errno));
        } else {
            /* We need to watch for attribute changes in addition to
             * creation, because when a device is first created, it has
             * permissions that we can't read. When udev chmods it to
             * something that we maybe *can* read, we'll get an
             * IN_ATTRIB event to tell us. */
            if (inotify_add_watch(inotify_fd, "/dev/input",
                                  IN_CREATE | IN_DELETE | IN_MOVE | IN_ATTRIB) < 0) {
                close(inotify_fd);
                inotify_fd = -1;
                SDL_LogWarn(SDL_LOG_CATEGORY_INPUT,
                            "Unable to add inotify watch, falling back to polling: %s",
                            strerror (errno));
            }
        }
#endif /* HAVE_INOTIFY */

        /* Report all devices currently present */
        LINUX_JoystickDetect();
    }

    return 0;
}
@@ -607,7 +799,7 @@
}

static int
allocate_hatdata(SDL_Joystick * joystick)
allocate_hatdata(SDL_Joystick *joystick)
{
    int i;

@@ -625,7 +817,7 @@
}

static int
allocate_balldata(SDL_Joystick * joystick)
allocate_balldata(SDL_Joystick *joystick)
{
    int i;

@@ -643,13 +835,14 @@
}

static void
ConfigJoystick(SDL_Joystick * joystick, int fd)
ConfigJoystick(SDL_Joystick *joystick, int fd)
{
    int i, t;
    unsigned long keybit[NBITS(KEY_MAX)] = { 0 };
    unsigned long absbit[NBITS(ABS_MAX)] = { 0 };
    unsigned long relbit[NBITS(REL_MAX)] = { 0 };
    unsigned long ffbit[NBITS(FF_MAX)] = { 0 };
    SDL_bool use_deadzones = SDL_GetHintBoolean(SDL_HINT_LINUX_JOYSTICK_DEADZONES, SDL_FALSE);

    /* See if this device uses the new unified event API */
    if ((ioctl(fd, EVIOCGBIT(EV_KEY, sizeof(keybit)), keybit) >= 0) &&
@@ -663,6 +856,7 @@
                printf("Joystick has button: 0x%x\n", i);
#endif
                joystick->hwdata->key_map[i] = joystick->nbuttons;
                joystick->hwdata->has_key[i] = SDL_TRUE;
                ++joystick->nbuttons;
            }
        }
@@ -672,6 +866,7 @@
                printf("Joystick has button: 0x%x\n", i);
#endif
                joystick->hwdata->key_map[i] = joystick->nbuttons;
                joystick->hwdata->has_key[i] = SDL_TRUE;
                ++joystick->nbuttons;
            }
        }
@@ -683,6 +878,7 @@
            }
            if (test_bit(i, absbit)) {
                struct input_absinfo absinfo;
                struct axis_correct *correct = &joystick->hwdata->abs_correct[i];

                if (ioctl(fd, EVIOCGABS(i), &absinfo) < 0) {
                    continue;
@@ -694,20 +890,26 @@
                       absinfo.fuzz, absinfo.flat);
#endif /* DEBUG_INPUT_EVENTS */
                joystick->hwdata->abs_map[i] = joystick->naxes;
                if (absinfo.minimum == absinfo.maximum) {
                    joystick->hwdata->abs_correct[i].used = 0;
                } else {
                    joystick->hwdata->abs_correct[i].used = 1;
                    joystick->hwdata->abs_correct[i].coef[0] =
                        (absinfo.maximum + absinfo.minimum) - 2 * absinfo.flat;
                    joystick->hwdata->abs_correct[i].coef[1] =
                        (absinfo.maximum + absinfo.minimum) + 2 * absinfo.flat;
                    t = ((absinfo.maximum - absinfo.minimum) - 4 * absinfo.flat);
                    if (t != 0) {
                        joystick->hwdata->abs_correct[i].coef[2] =
                            (1 << 28) / t;
                joystick->hwdata->has_abs[i] = SDL_TRUE;

                correct->minimum = absinfo.minimum;
                correct->maximum = absinfo.maximum;
                if (correct->minimum != correct->maximum) {
                    if (use_deadzones) {
                        correct->use_deadzones = SDL_TRUE;
                        correct->coef[0] = (absinfo.maximum + absinfo.minimum) - 2 * absinfo.flat;
                        correct->coef[1] = (absinfo.maximum + absinfo.minimum) + 2 * absinfo.flat;
                        t = ((absinfo.maximum - absinfo.minimum) - 4 * absinfo.flat);
                        if (t != 0) {
                            correct->coef[2] = (1 << 28) / t;
                        } else {
                            correct->coef[2] = 0;
                        }
                    } else {
                        joystick->hwdata->abs_correct[i].coef[2] = 0;
                        float value_range = (correct->maximum - correct->minimum);
                        float output_range = (SDL_JOYSTICK_AXIS_MAX - SDL_JOYSTICK_AXIS_MIN);

                        correct->scale = (output_range / value_range);
                    }
                }
                ++joystick->naxes;
@@ -728,6 +930,7 @@
                       absinfo.fuzz, absinfo.flat);
#endif /* DEBUG_INPUT_EVENTS */
                joystick->hwdata->hats_indices[hat_index] = joystick->nhats++;
                joystick->hwdata->has_hat[hat_index] = SDL_TRUE;
            }
        }
        if (test_bit(REL_X, relbit) || test_bit(REL_Y, relbit)) {
@@ -764,7 +967,7 @@
   It returns 0, or -1 if there is an error.
 */
static int
LINUX_JoystickOpen(SDL_Joystick * joystick, int device_index)
LINUX_JoystickOpen(SDL_Joystick *joystick, int device_index)
{
    SDL_joylist_item *item = JoystickByDevIndex(device_index);

@@ -817,13 +1020,13 @@
    item->hwdata = joystick->hwdata;

    /* mark joystick as fresh and ready */
    joystick->hwdata->fresh = 1;
    joystick->hwdata->fresh = SDL_TRUE;

    return (0);
}

static int
LINUX_JoystickRumble(SDL_Joystick * joystick, Uint16 low_frequency_rumble, Uint16 high_frequency_rumble)
LINUX_JoystickRumble(SDL_Joystick *joystick, Uint16 low_frequency_rumble, Uint16 high_frequency_rumble)
{
    struct input_event event;

@@ -864,8 +1067,32 @@
    return 0;
}

static int
LINUX_JoystickRumbleTriggers(SDL_Joystick *joystick, Uint16 left_rumble, Uint16 right_rumble)
{
    return SDL_Unsupported();
}

static SDL_bool
LINUX_JoystickHasLED(SDL_Joystick *joystick)
{
    return SDL_FALSE;
}

static int
LINUX_JoystickSetLED(SDL_Joystick *joystick, Uint8 red, Uint8 green, Uint8 blue)
{
    return SDL_Unsupported();
}

static int
LINUX_JoystickSetSensorsEnabled(SDL_Joystick *joystick, SDL_bool enabled)
{
    return SDL_Unsupported();
}

static SDL_INLINE void
HandleHat(SDL_Joystick * stick, Uint8 hat, int axis, int value)
HandleHat(SDL_Joystick *stick, Uint8 hat, int axis, int value)
{
    struct hwdata_hat *the_hat;
    const Uint8 position_map[3][3] = {
@@ -890,54 +1117,60 @@
}

static SDL_INLINE void
HandleBall(SDL_Joystick * stick, Uint8 ball, int axis, int value)
HandleBall(SDL_Joystick *stick, Uint8 ball, int axis, int value)
{
    stick->hwdata->balls[ball].axis[axis] += value;
}


static SDL_INLINE int
AxisCorrect(SDL_Joystick * joystick, int which, int value)
AxisCorrect(SDL_Joystick *joystick, int which, int value)
{
    struct axis_correct *correct;

    correct = &joystick->hwdata->abs_correct[which];
    if (correct->used) {
        value *= 2;
        if (value > correct->coef[0]) {
            if (value < correct->coef[1]) {
                return 0;
    if (correct->minimum != correct->maximum) {
        if (correct->use_deadzones) {
            value *= 2;
            if (value > correct->coef[0]) {
                if (value < correct->coef[1]) {
                    return 0;
                }
                value -= correct->coef[1];
            } else {
                value -= correct->coef[0];
            }
            value -= correct->coef[1];
            value *= correct->coef[2];
            value >>= 13;
        } else {
            value -= correct->coef[0];
            value = (int)SDL_floorf((value - correct->minimum) * correct->scale + SDL_JOYSTICK_AXIS_MIN + 0.5f);
        }
        value *= correct->coef[2];
        value >>= 13;
    }

    /* Clamp and return */
    if (value < -32768)
        return -32768;
    if (value > 32767)
        return 32767;

    if (value < SDL_JOYSTICK_AXIS_MIN) {
        return SDL_JOYSTICK_AXIS_MIN;
    }
    if (value > SDL_JOYSTICK_AXIS_MAX) {
        return SDL_JOYSTICK_AXIS_MAX;
    }
    return value;
}

static SDL_INLINE void
PollAllValues(SDL_Joystick * joystick)
PollAllValues(SDL_Joystick *joystick)
{
    struct input_absinfo absinfo;
    unsigned long keyinfo[NBITS(KEY_MAX)];
    int i;

    /* Poll all axis */
    for (i = ABS_X; i < ABS_MAX; i++) {
        if (i == ABS_HAT0X) {
        if (i == ABS_HAT0X) {  /* we handle hats in the next loop, skip them for now. */
            i = ABS_HAT3Y;
            continue;
        }
        if (joystick->hwdata->abs_correct[i].used) {
        if (joystick->hwdata->has_abs[i]) {
            if (ioctl(joystick->hwdata->fd, EVIOCGABS(i), &absinfo) >= 0) {
                absinfo.value = AxisCorrect(joystick, i, absinfo.value);

@@ -951,10 +1184,41 @@
            }
        }
    }

    /* Poll all hats */
    for (i = ABS_HAT0X; i <= ABS_HAT3Y; i++) {
        const int baseaxis = i - ABS_HAT0X;
        const int hatidx = baseaxis / 2;
        SDL_assert(hatidx < SDL_arraysize(joystick->hwdata->has_hat));
        if (joystick->hwdata->has_hat[hatidx]) {
            if (ioctl(joystick->hwdata->fd, EVIOCGABS(i), &absinfo) >= 0) {
                const int hataxis = baseaxis % 2;
                HandleHat(joystick, joystick->hwdata->hats_indices[hatidx], hataxis, absinfo.value);
            }
        }
    }

    /* Poll all buttons */
    SDL_zeroa(keyinfo);
    if (ioctl(joystick->hwdata->fd, EVIOCGKEY(sizeof (keyinfo)), keyinfo) >= 0) {
        for (i = 0; i < KEY_MAX; i++) {
            if (joystick->hwdata->has_key[i]) {
                const Uint8 value = test_bit(i, keyinfo) ? SDL_PRESSED : SDL_RELEASED;
#ifdef DEBUG_INPUT_EVENTS
                printf("Joystick : Re-read Button %d (%d) val= %d\n",
                    joystick->hwdata->key_map[i], i, value);
#endif
                SDL_PrivateJoystickButton(joystick,
                        joystick->hwdata->key_map[i], value);
            }
        }
    }

    /* Joyballs are relative input, so there's no poll state. Events only! */
}

static SDL_INLINE void
HandleInputEvents(SDL_Joystick * joystick)
HandleInputEvents(SDL_Joystick *joystick)
{
    struct input_event events[32];
    int i, len;
@@ -962,13 +1226,21 @@

    if (joystick->hwdata->fresh) {
        PollAllValues(joystick);
        joystick->hwdata->fresh = 0;
        joystick->hwdata->fresh = SDL_FALSE;
    }

    while ((len = read(joystick->hwdata->fd, events, (sizeof events))) > 0) {
        len /= sizeof(events[0]);
        for (i = 0; i < len; ++i) {
            code = events[i].code;

            /* If the kernel sent a SYN_DROPPED, we are supposed to ignore the
               rest of the packet (the end of it signified by a SYN_REPORT) */
            if ( joystick->hwdata->recovering_from_dropped &&
                 ((events[i].type != EV_SYN) || (code != SYN_REPORT)) ) {
                continue;
            }

            switch (events[i].type) {
            case EV_KEY:
                SDL_PrivateJoystickButton(joystick,
@@ -1016,7 +1288,13 @@
#ifdef DEBUG_INPUT_EVENTS
                    printf("Event SYN_DROPPED detected\n");
#endif
                    PollAllValues(joystick);
                    joystick->hwdata->recovering_from_dropped = SDL_TRUE;
                    break;
                case SYN_REPORT :
                    if (joystick->hwdata->recovering_from_dropped) {
                        joystick->hwdata->recovering_from_dropped = SDL_FALSE;
                        PollAllValues(joystick);  /* try to sync up to current state now */
                    }
                    break;
                default:
                    break;
@@ -1034,7 +1312,7 @@
}

static void
LINUX_JoystickUpdate(SDL_Joystick * joystick)
LINUX_JoystickUpdate(SDL_Joystick *joystick)
{
    int i;

@@ -1061,7 +1339,7 @@

/* Function to close a joystick after use */
static void
LINUX_JoystickClose(SDL_Joystick * joystick)
LINUX_JoystickClose(SDL_Joystick *joystick)
{
    if (joystick->hwdata) {
        if (joystick->hwdata->effect.id >= 0) {
@@ -1088,6 +1366,11 @@
    SDL_joylist_item *item = NULL;
    SDL_joylist_item *next = NULL;

    if (inotify_fd >= 0) {
        close(inotify_fd);
        inotify_fd = -1;
    }

    for (item = SDL_joylist; item; item = next) {
        next = item->next;
        SDL_free(item->path);
@@ -1100,11 +1383,187 @@
    numjoysticks = 0;

#if SDL_USE_LIBUDEV
    SDL_UDEV_DelCallback(joystick_udev_callback);
    SDL_UDEV_Quit();
    if (enumeration_method == ENUMERATION_LIBUDEV) {
        SDL_UDEV_DelCallback(joystick_udev_callback);
        SDL_UDEV_Quit();
    }
#endif

    SDL_QuitSteamControllers();
}

/*
   This is based on the Linux Gamepad Specification
   available at: https://www.kernel.org/doc/html/v4.15/input/gamepad.html
 */
static SDL_bool
LINUX_JoystickGetGamepadMapping(int device_index, SDL_GamepadMapping *out)
{
    SDL_Joystick *joystick;

    joystick = (SDL_Joystick *) SDL_calloc(sizeof(*joystick), 1);
    if (joystick == NULL) {
        SDL_OutOfMemory();
        return SDL_FALSE;
    }

    /* We temporarily open the device to check how it's configured. */
    if (LINUX_JoystickOpen(joystick, device_index) < 0) {
        SDL_free(joystick);
        return SDL_FALSE;
    }

    if (!joystick->hwdata->has_key[BTN_GAMEPAD]) {
        /* Not a gamepad according to the specs. */
        LINUX_JoystickClose(joystick);
        SDL_free(joystick);
        return SDL_FALSE;
    }

    /* We have a gamepad, start filling out the mappings */

    if (joystick->hwdata->has_key[BTN_SOUTH]) {
        out->a.kind = EMappingKind_Button;
        out->a.target = joystick->hwdata->key_map[BTN_SOUTH];
    }

    if (joystick->hwdata->has_key[BTN_EAST]) {
        out->b.kind = EMappingKind_Button;
        out->b.target = joystick->hwdata->key_map[BTN_EAST];
    }

    if (joystick->hwdata->has_key[BTN_NORTH]) {
        out->y.kind = EMappingKind_Button;
        out->y.target = joystick->hwdata->key_map[BTN_NORTH];
    }

    if (joystick->hwdata->has_key[BTN_WEST]) {
        out->x.kind = EMappingKind_Button;
        out->x.target = joystick->hwdata->key_map[BTN_WEST];
    }

    if (joystick->hwdata->has_key[BTN_SELECT]) {
        out->back.kind = EMappingKind_Button;
        out->back.target = joystick->hwdata->key_map[BTN_SELECT];
    }

    if (joystick->hwdata->has_key[BTN_START]) {
        out->start.kind = EMappingKind_Button;
        out->start.target = joystick->hwdata->key_map[BTN_START];
    }

    if (joystick->hwdata->has_key[BTN_THUMBL]) {
        out->leftstick.kind = EMappingKind_Button;
        out->leftstick.target = joystick->hwdata->key_map[BTN_THUMBL];
    }

    if (joystick->hwdata->has_key[BTN_THUMBR]) {
        out->rightstick.kind = EMappingKind_Button;
        out->rightstick.target = joystick->hwdata->key_map[BTN_THUMBR];
    }

    if (joystick->hwdata->has_key[BTN_MODE]) {
        out->guide.kind = EMappingKind_Button;
        out->guide.target = joystick->hwdata->key_map[BTN_MODE];
    }

    /*
       According to the specs the D-Pad, the shoulder buttons and the triggers
       can be digital, or analog, or both at the same time.
     */

    /* Prefer digital shoulder buttons, but settle for analog if missing. */
    if (joystick->hwdata->has_key[BTN_TL]) {
        out->leftshoulder.kind = EMappingKind_Button;
        out->leftshoulder.target = joystick->hwdata->key_map[BTN_TL];
    }

    if (joystick->hwdata->has_key[BTN_TR]) {
        out->rightshoulder.kind = EMappingKind_Button;
        out->rightshoulder.target = joystick->hwdata->key_map[BTN_TR];
    }

    if (joystick->hwdata->has_hat[1] && /* Check if ABS_HAT1{X, Y} is available. */
       (!joystick->hwdata->has_key[BTN_TL] || !joystick->hwdata->has_key[BTN_TR])) {
        int hat = joystick->hwdata->hats_indices[1] << 4;
        out->leftshoulder.kind = EMappingKind_Hat;
        out->rightshoulder.kind = EMappingKind_Hat;
        out->leftshoulder.target = hat | 0x4;
        out->rightshoulder.target = hat | 0x2;
    }

    /* Prefer analog triggers, but settle for digital if missing. */
    if (joystick->hwdata->has_hat[2]) { /* Check if ABS_HAT2{X,Y} is available. */
        int hat = joystick->hwdata->hats_indices[2] << 4;
        out->lefttrigger.kind = EMappingKind_Hat;
        out->righttrigger.kind = EMappingKind_Hat;
        out->lefttrigger.target = hat | 0x4;
        out->righttrigger.target = hat | 0x2;
    } else {
        if (joystick->hwdata->has_key[BTN_TL2]) {
            out->lefttrigger.kind = EMappingKind_Button;
            out->lefttrigger.target = joystick->hwdata->key_map[BTN_TL2];
        }

        if (joystick->hwdata->has_key[BTN_TR2]) {
            out->righttrigger.kind = EMappingKind_Button;
            out->righttrigger.target = joystick->hwdata->key_map[BTN_TR2];
        }
    }

    /* Prefer digital D-Pad, but settle for analog if missing. */
    if (joystick->hwdata->has_key[BTN_DPAD_UP]) {
        out->dpup.kind = EMappingKind_Button;
        out->dpup.target = joystick->hwdata->key_map[BTN_DPAD_UP];
    }

    if (joystick->hwdata->has_key[BTN_DPAD_DOWN]) {
        out->dpdown.kind = EMappingKind_Button;
        out->dpdown.target = joystick->hwdata->key_map[BTN_DPAD_DOWN];
    }

    if (joystick->hwdata->has_key[BTN_DPAD_LEFT]) {
        out->dpleft.kind = EMappingKind_Button;
        out->dpleft.target = joystick->hwdata->key_map[BTN_DPAD_LEFT];
    }

    if (joystick->hwdata->has_key[BTN_DPAD_RIGHT]) {
        out->dpright.kind = EMappingKind_Button;
        out->dpright.target = joystick->hwdata->key_map[BTN_DPAD_RIGHT];
    }

    if (joystick->hwdata->has_hat[0] && /* Check if ABS_HAT0{X,Y} is available. */
       (!joystick->hwdata->has_key[BTN_DPAD_LEFT] || !joystick->hwdata->has_key[BTN_DPAD_RIGHT] ||
        !joystick->hwdata->has_key[BTN_DPAD_UP] || !joystick->hwdata->has_key[BTN_DPAD_DOWN])) {
       int hat = joystick->hwdata->hats_indices[0] << 4;
       out->dpleft.kind = EMappingKind_Hat;
       out->dpright.kind = EMappingKind_Hat;
       out->dpup.kind = EMappingKind_Hat;
       out->dpdown.kind = EMappingKind_Hat;
       out->dpleft.target = hat | 0x8;
       out->dpright.target = hat | 0x2;
       out->dpup.target = hat | 0x1;
       out->dpdown.target = hat | 0x4;
    }

    if (joystick->hwdata->has_abs[ABS_X] && joystick->hwdata->has_abs[ABS_Y]) {
        out->leftx.kind = EMappingKind_Axis;
        out->lefty.kind = EMappingKind_Axis;
        out->leftx.target = joystick->hwdata->abs_map[ABS_X];
        out->lefty.target = joystick->hwdata->abs_map[ABS_Y];
    }

    if (joystick->hwdata->has_abs[ABS_RX] && joystick->hwdata->has_abs[ABS_RY]) {
        out->rightx.kind = EMappingKind_Axis;
        out->righty.kind = EMappingKind_Axis;
        out->rightx.target = joystick->hwdata->abs_map[ABS_RX];
        out->righty.target = joystick->hwdata->abs_map[ABS_RY];
    }

    LINUX_JoystickClose(joystick);
    SDL_free(joystick);

    return SDL_TRUE;
}

SDL_JoystickDriver SDL_LINUX_JoystickDriver =
@@ -1119,9 +1578,14 @@
    LINUX_JoystickGetDeviceInstanceID,
    LINUX_JoystickOpen,
    LINUX_JoystickRumble,
    LINUX_JoystickRumbleTriggers,
    LINUX_JoystickHasLED,
    LINUX_JoystickSetLED,
    LINUX_JoystickSetSensorsEnabled,
    LINUX_JoystickUpdate,
    LINUX_JoystickClose,
    LINUX_JoystickQuit,
    LINUX_JoystickGetGamepadMapping
};

#endif /* SDL_JOYSTICK_LINUX */