ESP32 Forum

Posted: **Fri Sep 09, 2022 6:12 am**

Hi!
Is it possible to use Bluetooth SPP in VFS mode with select()?
I'm trying to implement non-blocking reading, but my application crashes at select() operation.
write() and read() to the SPP file descriptor works fine.
Code example:

Code: [Select all] [Expand/Collapse]

static void spp_read_handle(void *param)
{
    int size = 0;
    int read_bytes;
    int spp_fd = (int)param;
 
    uint8_t *spp_data = (uint8_t *)malloc(SPP_DATA_LEN);
    if (!spp_data) {
        ESP_LOGE(TAG, "malloc spp_data failed, fd:%d", spp_fd);
    }
 
    while (true) {
        int s = 0;
        fd_set rfds;
        struct timeval tv = {
            .tv_sec = 5,
            .tv_usec = 0,
        };
 
        FD_ZERO(&rfds);
        FD_SET(spp_fd, &rfds);
 
        s = select(spp_fd + 1, &rfds, NULL, NULL, &tv); // crashed here
 
        if (s < 0) {
            ESP_LOGE(TAG, "Select failed: errno %d", errno);
        } else if (s == 0) {
            ESP_LOGI(TAG, "Timeout has been reached and nothing has been received");
        } else {
            ESP_LOGE(TAG, "Select: data is ready for reading");
        }
    };
}

GeSHi © Codebox Plus Extension

Panic back trace, but it's not so usefull:

Code: Select all

Guru Meditation Error: Core  0 panic'ed (Instr
FetchProhibited). Exception was unhandled.                                                                                          
                                                                                                                                    
Core  0 register dump:                                                                                                              
PC      : 0x00000000  PS      : 0x00060230  A0      : 0x800f38a6  A1      : 0x3fffa540                                              
A2      : 0x3ffef6f0  A3      : 0x00000005  A4      : 0x00000001  A5      : 0x00000000                                              
A6      : 0x00000005  A7      : 0x3ffc311c  A8      : 0x800d3d60  A9      : 0x3fffa520                                              
A10     : 0x00000000  A11     : 0x0000001c  A12     : 0x80095cf5  A13     : 0x3ffdb7d0                                              
A14     : 0x00000003  A15     : 0x00060323  SAR     : 0x0000001b  EXCCAUSE: 0x00000014                                              
EXCVADDR: 0x00000000  LBEG    : 0x00000000  LEND    : 0x00000000  LCOUNT  : 0x00000000                                              
                                                                                                                                    
                                                                                                                                    
Backtrace:0xfffffffd:0x3fffa5400x400f38a3:0x3fffa5b0 0x40095b9d:0x3fffa5e0                                                          
0x400f38a3: spp_read_handle(void*) at /home/ilia.lutchenko/workspace/project/build/../firmware/bluetooth/bt_classic.cpp:115        
                                                                                                                                    
0x40095b9d: vPortTaskWrapper at /home/ilia.lutchenko/workspace/project/build/../esp-idf/components/freertos/port/xtensa/port.c:131

Posted: **Thu Jul 27, 2023 12:50 am**

Hello, did you solve the problem? I've met it now. Thank you.

ESP32 Forum

Bluetooth SPP in VFS mode and select()

Bluetooth SPP in VFS mode and select()

Re: Bluetooth SPP in VFS mode and select()