1 files changed, 4 insertions, 3 deletions

diff --git a/src/device.c b/src/device.c
index e36509e..1c8ec8c 100644
--- a/src/device.c
+++ b/src/device.c
@@ -424,9 +424,9 @@ void device_client_process(int device_id, struct mux_client *client, short event
 
         int res;
         int size;
-        if(events & POLLOUT) {
+        if((events & POLLOUT) && conn->ib_size > 0) {
                 // Client is ready to receive data, send what we have
-                // in the client's connection buffer
+                // in the client's connection buffer (if there is any)
                 size = client_write(conn->client, conn->ib_buf, conn->ib_size);
                 if(size <= 0) {
                         usbmuxd_log(LL_DEBUG, "error writing to client (%d)", size);
@@ -441,9 +441,10 @@ void device_client_process(int device_id, struct mux_client *client, short event
                         memmove(conn->ib_buf, conn->ib_buf + size, conn->ib_size);
                 }
         }
-        if(events & POLLIN) {
+        if((events & POLLIN) && conn->sendable > 0) {
                 // There is inbound trafic on the client socket,
                 // convert it to tcp and send to the device
+                // (if the device's input buffer is not full)
                 size = client_read(conn->client, conn->ob_buf, conn->sendable);
                 if(size <= 0) {
                         if (size < 0) {