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-rw-r--r--tmk_core/protocol/chibios/usb_driver.c14
1 files changed, 13 insertions, 1 deletions
diff --git a/tmk_core/protocol/chibios/usb_driver.c b/tmk_core/protocol/chibios/usb_driver.c
index cc0ce7600f..eb72f8ff6d 100644
--- a/tmk_core/protocol/chibios/usb_driver.c
+++ b/tmk_core/protocol/chibios/usb_driver.c
@@ -80,7 +80,19 @@ static bool qmkusb_start_receive(QMKUSBDriver *qmkusbp) {
* Interface implementation.
*/
-static size_t _write(void *ip, const uint8_t *bp, size_t n) { return obqWriteTimeout(&((QMKUSBDriver *)ip)->obqueue, bp, n, TIME_INFINITE); }
+static size_t _write(void *ip, const uint8_t *bp, size_t n) {
+ output_buffers_queue_t *obqueue = &((QMKUSBDriver *)ip)->obqueue;
+ chSysLock();
+ const bool full = obqIsFullI(obqueue);
+ chSysUnlock();
+ if (full || bqIsSuspendedX(obqueue)) {
+ /* Discard any writes while the queue is suspended or full, i.e. the hidraw
+ interface is not open. If we tried to send with an infinite timeout, we
+ would deadlock the keyboard otherwise. */
+ return -1;
+ }
+ return obqWriteTimeout(obqueue, bp, n, TIME_INFINITE);
+}
static size_t _read(void *ip, uint8_t *bp, size_t n) { return ibqReadTimeout(&((QMKUSBDriver *)ip)->ibqueue, bp, n, TIME_INFINITE); }