Hi everyone,<div>I find an interesting problem when I read the code of endpoint(kernel\src\object\endpoint.c). In the sendIPC and receiveIPC functions , I see there are 3 states for an endpoint(Idle , send , receive). Below it is the state machine diagram.<span style="color: rgb(67, 67, 67); font-family: Tahoma, Arial, 卜悶, 'Malgun Gothic'; font-size: 12px; font-weight: bold; line-height: 19.1875px; widows: auto; background-color: rgb(242, 242, 242);"></span></div><div>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;sendIPC</div><div>EPState_Recv ！！&gt;&nbsp;<span style="line-height: 1.5;">EPState_</span><span style="line-height: 1.5;">Idle ！！&gt;</span><span style="line-height: 1.5;">EPState_</span><span style="line-height: 1.5;">send</span></div><div><span style="line-height: 1.5;"><br></span></div><div><div style="line-height: 21px;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;receiveIPC</div><div style="line-height: 21px;"><span style="line-height: 1.5;">EPState_</span><span style="line-height: 1.5;">send</span>！！&gt;&nbsp;<span style="line-height: 1.5;">EPState_</span><span style="line-height: 1.5;">Idle ！！&gt;</span><span style="line-height: 1.5;"></span><span style="line-height: 1.5;">EPState_Recv</span><span style="line-height: 1.5;">&nbsp;</span></div></div><div style="line-height: 21px;"><span style="line-height: 1.5;"><br></span></div><div style="line-height: 21px;"><span style="line-height: 1.5;"><br></span></div><div style="line-height: 21px;">But when I add some print infomation, I find the endpoint can never reach the Send state. I think the correct state machine diagram just has two states(idle and receive).</div><div style="line-height: 21px;"><div style="line-height: 21px;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;sendIPC</div><div style="line-height: 21px;">EPState_Recv ！！&gt;&nbsp;<span style="line-height: 1.5;">EPState_</span><span style="line-height: 1.5;">Idle</span></div><div style="line-height: 21px;"><span style="line-height: 1.5;"><br></span></div><div style="line-height: 21px;"><div style="line-height: 21px;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;receiveIPC</div><div style="line-height: 21px;"><span style="line-height: 1.5;">EPState_</span><span style="line-height: 1.5;">Idle ！！&gt;</span><span style="line-height: 1.5;"></span><span style="line-height: 1.5;">EPState_Recv</span><span style="line-height: 1.5;">&nbsp;</span></div></div></div><div style="line-height: 21px;"><br></div><div style="line-height: 21px;">Am I right???</div>