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<p class="MsoNormal">Hello world\n<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I’m observing a 256 byte input limit with RTEMS 5 on riscv that I don’t know how to overcome.<o:p></o:p></p>
<p class="MsoNormal">We are using the RTEMS console driver and newlib stdio.<o:p></o:p></p>
<p class="MsoNormal">The effect is that an fgets() appears to only accept 256 characters, specifically if we connect via<o:p></o:p></p>
<p class="MsoNormal">picocom on a Linux box, we can type exactly 256 chars and then no more characters are accepted.<o:p></o:p></p>
<p class="MsoNormal">My first guess was that stdio buffers are 256 byte by default, which they seem to be judging from<o:p></o:p></p>
<p class="MsoNormal">grepping for BUFSIZ. Then using setvbuf should be the way to increase their size. But setvbuf had no effect.<o:p></o:p></p>
<p class="MsoNormal">Next guess was that it is a limit of picocom. So we tried using Python with pyserial to send data.<o:p></o:p></p>
<p class="MsoNormal">Same problem.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Here’s a complete RTEMS application that has this issue. How can we increase the input buffer size?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">#include <rtems.h><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">#include <stdio.h><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">#include <string.h><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">/*<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">* RTEMS OS Configuration definitions<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">*/<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">#define CONFIGURE_INIT<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">#define CONFIGURE_INIT_TASK_STACK_SIZE 24576<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">#define CONFIGURE_INIT_TASK_ATTRIBUTES RTEMS_FLOATING_POINT<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">#define CONFIGURE_APPLICATION_NEEDS_CONSOLE_DRIVER<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">#define CONFIGURE_APPLICATION_NEEDS_CLOCK_DRIVER<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">#define CONFIGURE_MAXIMUM_TASKS 2<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">#define CONFIGURE_RTEMS_INIT_TASKS_TABLE<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">#define CONFIGURE_MAXIMUM_DRIVERS 10<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">#define CONFIGURE_MAXIMUM_USER_EXTENSIONS 2<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">#include <rtems/shellconfig.h><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">#include <rtems/confdefs.h><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">rtems_task Init(rtems_task_argument aUnused);<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">rtems_task Init(rtems_task_argument aUnused) {<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> char i_buf[1536];<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> char o_buf[1536];<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> printf("Welcome!\n");<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> if (setvbuf(stdin, i_buf, _IONBF, sizeof i_buf) != 0) {<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> printf("setvbuf i buf failed.\n");<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> }<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> if (setvbuf(stdout, o_buf, _IONBF, sizeof o_buf) != 0) {<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> printf("setvbuf o buf failed.\n");<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> }<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> rtems_task_wake_after(10);<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> fflush(stdout);<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> for (;;) {<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> printf(">> ");<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> char command_line[1536];<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> if (fgets(command_line, sizeof command_line, stdin) == NULL) {<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> printf("fgets returned NULL\n");<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> break;<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> }<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> printf("%zu bytes: %s\n", strlen(command_line), command_line);<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> }<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> (void) rtems_task_delete(RTEMS_SELF);<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">}<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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