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25f9f55878
I consider to remove the PPP_INPROC_OWNTHREAD crap in ppp-new, as said in bugs #37278 and #37353. 1. It requires the ppp_input_thread() function to be modified to match user system, like some did by adding the vTaskDelete(NULL); FreeRTOS call at the end of the function, for example. This is a tiny-tiny fonction that should be, in my opinion, on the user port, like the Ethernet input thread we see in many Ethernet port. 2. It is actually not that thread safe. 2.1. pcb->phase IS modified by the lwIP core thread so it should at least be set to volatile, otherwise the pcb->phase copy may live indefinitely in CPU register. It works because of the sio_read() function call which without doubt flush pcb->phase copy from CPU register. I dont want to set ppp_pcb struct to volatile for obvious performance reasons. 2.2. This function assume PCB still exists whatever is happening, which is not the case after you called ppp_delete() function outside of this thread. If sio_read() is blocking waiting data and pcb destroyed, it is going to read a deallocated pcb which luckily should still have pcb->phase set to 0 (=PHASE_DEAD) due to preallocated "control block" structures of lwIP. Even with sio_read_abort(), there might be timings issue due to a lack of a synchronization mechanism. 3. I dislike the sys_msleep(1), it means that systems should have at least a 11 chr buffer at 115200/10 byte/s, and bigger with higher serial speed, for example with 3G/HSDPA modems accessed through SPI, at 20 Mbits/s this is a ~2000 bytes buffer required to keep incoming data during this sleep, I don't see why we require systems to do so, sio_read() should obviously be a blocking call. I cannot easily remove this sleep because some systems might have wrongfully used this call as a CPU idle feature with a non blocking sio_read() call.