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Don't block in Android USB device open
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We might be waiting a long time for a permissions dialog, so let that complete asynchronously. While that's happening, we'll remove the device from the device list so that when we get permission the application sees the device as newly available and can open it again.

Fixes libsdl-org#6347
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@slouken
slouken committed Oct 17, 2024
1 parent 60c3eaf commit 41366f7
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Showing 2 changed files with 76 additions and 87 deletions.
113 changes: 76 additions & 37 deletions src/hidapi/android/hid.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -500,46 +500,38 @@ class CHIDDevice
return false;
}

m_bIsWaitingForOpen = false;
m_bOpenResult = env->CallBooleanMethod( g_HIDDeviceManagerCallbackHandler, g_midHIDDeviceManagerOpen, m_nId );
ExceptionCheck( env, "BOpen" );

if ( m_bIsWaitingForOpen )
{
hid_mutex_guard cvl( &m_cvLock );

const int OPEN_TIMEOUT_SECONDS = 60;
struct timespec ts, endtime;
clock_gettime( CLOCK_REALTIME, &ts );
endtime = ts;
endtime.tv_sec += OPEN_TIMEOUT_SECONDS;
do
{
if ( pthread_cond_timedwait( &m_cv, &m_cvLock, &endtime ) != 0 )
{
break;
}
}
while ( m_bIsWaitingForOpen && get_timespec_ms( ts ) < get_timespec_ms( endtime ) );
SDL_SetError( "Waiting for permission" );
return false;
}

if ( !m_bOpenResult )
{
m_bOpenResult = env->CallBooleanMethod( g_HIDDeviceManagerCallbackHandler, g_midHIDDeviceManagerOpen, m_nId );
ExceptionCheck( env, "BOpen" );

if ( m_bIsWaitingForOpen )
{
LOGV( "Device open failed - timed out waiting for device permission" );
LOGV( "Device open waiting for permission" );
SDL_SetError( "Waiting for permission" );
m_bWasOpenPending = true;
return false;
}
else

if ( !m_bOpenResult )
{
LOGV( "Device open failed" );
SDL_SetError( "Device open failed" );
return false;
}
return false;
}

m_pDevice = new hid_device;
m_pDevice->m_nId = m_nId;
m_pDevice->m_nDeviceRefCount = 1;
LOGD("Creating device %d (%p), refCount = 1\n", m_pDevice->m_nId, m_pDevice);

return true;
}

Expand All @@ -548,16 +540,44 @@ class CHIDDevice
m_bIsWaitingForOpen = true;
}

bool BOpenPending() const
{
return m_bIsWaitingForOpen;
}

void SetWasOpenPending( bool bState )
{
m_bWasOpenPending = bState;
}

bool BWasOpenPending() const
{
return m_bWasOpenPending;
}

void SetOpenResult( bool bResult )
{
if ( m_bIsWaitingForOpen )
{
m_bOpenResult = bResult;
m_bIsWaitingForOpen = false;
pthread_cond_signal( &m_cv );

if ( m_bOpenResult )
{
LOGV( "Device open succeeded" );
}
else
{
LOGV( "Device open failed" );
}
}
}

bool BOpenResult() const
{
return m_bOpenResult;
}

void ProcessInput( const uint8_t *pBuf, size_t nBufSize )
{
hid_mutex_guard l( &m_dataLock );
Expand Down Expand Up @@ -606,18 +626,16 @@ class CHIDDevice
{
JNIEnv *env = SDL_GetAndroidJNIEnv();

int nRet = -1;
if ( g_HIDDeviceManagerCallbackHandler )
{
jbyteArray pBuf = NewByteArray( env, pData, nDataLen );
nRet = env->CallIntMethod( g_HIDDeviceManagerCallbackHandler, g_midHIDDeviceManagerWriteReport, m_nId, pBuf, bFeature );
ExceptionCheck( env, "WriteReport" );
env->DeleteLocalRef( pBuf );
}
else
if ( !g_HIDDeviceManagerCallbackHandler )
{
LOGV( "WriteReport without callback handler" );
return -1;
}

jbyteArray pBuf = NewByteArray( env, pData, nDataLen );
int nRet = env->CallIntMethod( g_HIDDeviceManagerCallbackHandler, g_midHIDDeviceManagerWriteReport, m_nId, pBuf, bFeature );
ExceptionCheck( env, "WriteReport" );
env->DeleteLocalRef( pBuf );
return nRet;
}

Expand Down Expand Up @@ -713,8 +731,11 @@ class CHIDDevice

if ( g_HIDDeviceManagerCallbackHandler )
{
env->CallVoidMethod( g_HIDDeviceManagerCallbackHandler, g_midHIDDeviceManagerClose, m_nId );
ExceptionCheck( env, "Close" );
if ( !m_bIsWaitingForOpen && m_bOpenResult )
{
env->CallVoidMethod( g_HIDDeviceManagerCallbackHandler, g_midHIDDeviceManagerClose, m_nId );
ExceptionCheck( env, "Close" );
}
}

hid_mutex_guard dataLock( &m_dataLock );
Expand Down Expand Up @@ -749,6 +770,7 @@ class CHIDDevice
pthread_mutex_t m_cvLock = PTHREAD_MUTEX_INITIALIZER; // This lock has to be held to access any variables below
pthread_cond_t m_cv = PTHREAD_COND_INITIALIZER;
bool m_bIsWaitingForOpen = false;
bool m_bWasOpenPending = false;
bool m_bOpenResult = false;
bool m_bIsWaitingForReportResponse = false;
int m_nReportResponseError = 0;
Expand Down Expand Up @@ -1045,6 +1067,18 @@ struct hid_device_info HID_API_EXPORT * HID_API_CALL hid_enumerate(unsigned shor
hid_mutex_guard l( &g_DevicesMutex );
for ( hid_device_ref<CHIDDevice> pDevice = g_Devices; pDevice; pDevice = pDevice->next )
{
// Don't enumerate devices that are currently being opened, we'll re-enumerate them when we're done
// Make sure we skip them at least once, so they get removed and then re-added to the caller's device list
if ( pDevice->BWasOpenPending() )
{
// Don't enumerate devices that failed to open, otherwise the application might try to keep prompting for access
if ( !pDevice->BOpenPending() && pDevice->BOpenResult() )
{
pDevice->SetWasOpenPending( false );
}
continue;
}

const hid_device_info *info = pDevice->GetDeviceInfo();

/* See if there are any devices we should skip in enumeration */
Expand Down Expand Up @@ -1105,7 +1139,12 @@ HID_API_EXPORT hid_device * HID_API_CALL hid_open_path(const char *path)
}
}
}
if ( pDevice && pDevice->BOpen() )
if ( !pDevice )
{
SDL_SetError( "Couldn't find device with path %s", path );
return NULL;
}
if ( pDevice->BOpen() )
{
return pDevice->GetDevice();
}
Expand All @@ -1116,7 +1155,7 @@ int HID_API_EXPORT HID_API_CALL hid_write(hid_device *device, const unsigned ch
{
if ( device )
{
LOGV( "hid_write id=%d length=%zu", device->m_nId, length );
// LOGV( "hid_write id=%d length=%zu", device->m_nId, length );
hid_device_ref<CHIDDevice> pDevice = FindDevice( device->m_nId );
if ( pDevice )
{
Expand Down Expand Up @@ -1180,7 +1219,7 @@ int HID_API_EXPORT HID_API_CALL hid_read_timeout(hid_device *device, unsigned ch
// TODO: Implement blocking
int HID_API_EXPORT HID_API_CALL hid_read(hid_device *device, unsigned char *data, size_t length)
{
LOGV( "hid_read id=%d length=%zu", device->m_nId, length );
// LOGV( "hid_read id=%d length=%zu", device->m_nId, length );
return hid_read_timeout( device, data, length, 0 );
}

Expand Down
50 changes: 0 additions & 50 deletions src/joystick/hidapi/SDL_hidapijoystick.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -454,57 +454,7 @@ static void HIDAPI_SetupDeviceDriver(SDL_HIDAPI_Device *device, bool *removed) S
// Wait a little bit for the device to initialize
SDL_Delay(10);

#ifdef SDL_PLATFORM_ANDROID
/* On Android we need to leave joysticks unlocked because it calls
* out to the main thread for permissions and the main thread can
* be in the process of handling controller input.
*
* See https://github.com/libsdl-org/SDL/issues/6347 for details
*/
{
SDL_HIDAPI_Device *curr;
int lock_count = 0;
char *path = SDL_strdup(device->path);

SDL_AssertJoysticksLocked();
while (SDL_JoysticksLocked()) {
++lock_count;
SDL_UnlockJoysticks();
}

dev = SDL_hid_open_path(path);

while (lock_count > 0) {
--lock_count;
SDL_LockJoysticks();
}
SDL_free(path);

// Make sure the device didn't get removed while opening the HID path
for (curr = SDL_HIDAPI_devices; curr && curr != device; curr = curr->next) {
continue;
}
if (curr == NULL) {
*removed = true;
if (dev) {
SDL_hid_close(dev);
}
return;
}
}
#else
/* On other platforms we want to keep the lock so other threads wait for
* us to finish opening the controller before checking to see whether the
* HIDAPI driver is handling the device.
*
* On Windows, for example, the main thread can be enumerating DirectInput
* devices while the Windows.Gaming.Input thread is calling back with a new
* controller available.
*
* See https://github.com/libsdl-org/SDL/issues/7304 for details.
*/
dev = SDL_hid_open_path(device->path);
#endif

if (dev == NULL) {
SDL_LogDebug(SDL_LOG_CATEGORY_INPUT,
Expand Down

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