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Avoid opening non-joystick devices if possible to speedup scanning

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Closing a device file takes 0.01 to 0.5s, which can add up to
significant startup delays. The udev classification does not
require opening the actual device files, so, use it if possible,
and only fall back to opening the device and probing otherwise.
This commit is contained in:
Tyson Whitehead
2024-04-04 12:17:42 -04:00
committed by Sam Lantinga
parent 0963c11af8
commit 45b804c158
1 changed files with 57 additions and 19 deletions
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76
src/joystick/linux/SDL_sysjoystick.c
View File

@@ -273,7 +273,7 @@ static int GuessIsSensor(int fd)
return 0;
}
static int IsJoystick(const char *path, int fd, char **name_return, Uint16 *vendor_return, Uint16 *product_return, SDL_JoystickGUID *guid)
static int IsJoystick(const char *path, int *fd, char **name_return, Uint16 *vendor_return, Uint16 *product_return, SDL_JoystickGUID *guid)
{
struct input_id inpid;
char *name;
@@ -282,21 +282,32 @@ static int IsJoystick(const char *path, int fd, char **name_return, Uint16 *vend
SDL_zero(inpid);
#ifdef SDL_USE_LIBUDEV
SDL_UDEV_GetProductInfo(path, &inpid.vendor, &inpid.product, &inpid.version, &class);
/* Opening input devices can generate synchronous device I/O, so avoid it if we can */
if (SDL_UDEV_GetProductInfo(path, &inpid.vendor, &inpid.product, &inpid.version, &class) &&
!(class & SDL_UDEV_DEVICE_JOYSTICK)) {
return 0;
}
#endif
if (ioctl(fd, JSIOCGNAME(sizeof(product_string)), product_string) <= 0) {
/* When udev is enabled we only get joystick devices here, so there's no need to test them */
if (enumeration_method != ENUMERATION_LIBUDEV &&
!(class & SDL_UDEV_DEVICE_JOYSTICK) && ( class || !GuessIsJoystick(fd))) {
if (fd && *fd < 0) {
*fd = open(path, O_RDONLY | O_CLOEXEC, 0);
}
if (!fd || *fd < 0) {
return 0;
}
if (ioctl(*fd, JSIOCGNAME(sizeof(product_string)), product_string) <= 0) {
/* When udev enumeration or classification, we only got joysticks here, so no need to test */
if (enumeration_method != ENUMERATION_LIBUDEV && !class && !GuessIsJoystick(*fd)) {
return 0;
}
/* Could have vendor and product already from udev, but should agree with evdev */
if (ioctl(fd, EVIOCGID, &inpid) < 0) {
if (ioctl(*fd, EVIOCGID, &inpid) < 0) {
return 0;
}
if (ioctl(fd, EVIOCGNAME(sizeof(product_string)), product_string) < 0) {
if (ioctl(*fd, EVIOCGNAME(sizeof(product_string)), product_string) < 0) {
return 0;
}
}
@@ -315,7 +326,7 @@ static int IsJoystick(const char *path, int fd, char **name_return, Uint16 *vend
}
#endif
FixupDeviceInfoForMapping(fd, &inpid);
FixupDeviceInfoForMapping(*fd, &inpid);
#ifdef DEBUG_JOYSTICK
SDL_Log("Joystick: %s, bustype = %d, vendor = 0x%.4x, product = 0x%.4x, version = %d\n", name, inpid.bustype, inpid.vendor, inpid.product, inpid.version);
@@ -333,11 +344,32 @@ static int IsJoystick(const char *path, int fd, char **name_return, Uint16 *vend
return 1;
}
static int IsSensor(const char *path, int fd)
static int IsSensor(const char *path, int *fd)
{
struct input_id inpid;
int class = 0;
if (ioctl(fd, EVIOCGID, &inpid) < 0) {
SDL_zero(inpid);
#ifdef SDL_USE_LIBUDEV
/* Opening input devices can generate synchronous device I/O, so avoid it if we can */
if (SDL_UDEV_GetProductInfo(path, &inpid.vendor, &inpid.product, &inpid.version, &class) &&
!(class & SDL_UDEV_DEVICE_ACCELEROMETER)) {
return 0;
}
#endif
if (fd && *fd < 0) {
*fd = open(path, O_RDONLY | O_CLOEXEC, 0);
}
if (!fd || *fd < 0) {
return 0;
}
if (!class && !GuessIsSensor(*fd)) {
return 0;
}
if (ioctl(*fd, EVIOCGID, &inpid) < 0) {
return 0;
}
@@ -347,7 +379,7 @@ static int IsSensor(const char *path, int fd)
return 0;
}
return GuessIsSensor(fd);
return 1;
}
#ifdef SDL_USE_LIBUDEV
@@ -434,16 +466,11 @@ static void MaybeAddDevice(const char *path)
}
}
fd = open(path, O_RDONLY | O_CLOEXEC, 0);
if (fd < 0) {
goto done;
}
#ifdef DEBUG_INPUT_EVENTS
SDL_Log("Checking %s\n", path);
#endif
if (IsJoystick(path, fd, &name, &vendor, &product, &guid)) {
if (IsJoystick(path, &fd, &name, &vendor, &product, &guid)) {
#ifdef DEBUG_INPUT_EVENTS
SDL_Log("found joystick: %s\n", path);
#endif
@@ -484,7 +511,7 @@ static void MaybeAddDevice(const char *path)
goto done;
}
if (IsSensor(path, fd)) {
if (IsSensor(path, &fd)) {
#ifdef DEBUG_INPUT_EVENTS
SDL_Log("found sensor: %s\n", path);
#endif
@@ -880,11 +907,22 @@ static void LINUX_ScanSteamVirtualGamepads(void)
int num_virtual_gamepads = 0;
int virtual_gamepad_slot;
VirtualGamepadEntry *virtual_gamepads = NULL;
int class;
count = scandir("/dev/input", &entries, filter_entries, NULL);
for (i = 0; i < count; ++i) {
(void)SDL_snprintf(path, SDL_arraysize(path), "/dev/input/%s", entries[i]->d_name);
#ifdef SDL_USE_LIBUDEV
/* Opening input devices can generate synchronous device I/O, so avoid it if we can */
class = 0;
SDL_zero(inpid);
if (SDL_UDEV_GetProductInfo(path, &inpid.vendor, &inpid.product, &inpid.version, &class) &&
(inpid.vendor != USB_VENDOR_VALVE || inpid.product != USB_PRODUCT_STEAM_VIRTUAL_GAMEPAD)) {
free(entries[i]); /* This should NOT be SDL_free() */
continue;
}
#endif
fd = open(path, O_RDONLY | O_CLOEXEC, 0);
if (fd >= 0) {
if (ioctl(fd, EVIOCGID, &inpid) == 0 &&