AM62P-Q1: How to detect frame freeze on camera video flow

Hi Chunfu,

You should be able to detect CSI frame freeze by timing the DMA callback of the CSIRX driver. For example, you can add some code at this line to get the time when DMA callback is invoked: https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/drivers/media/platform/ti/j721e-csi2rx/j721e-csi2rx.c?h=ti-linux-6.6.y#n747.

    pthread_mutex_lock(&freeze_detect_timer_mutex); 
    last_dma_callback_time = time(NULL); 
    pthread_mutex_unlock(&freeze_detect_timer_mutex); 

Then in your application code, periodically check how much time is elapsed since last CSIRX DMA callback:

    current_time = time(NULL); 
    pthread_mutex_lock(&freeze_detect_timer_mutex); 
    time_elapsed = difftime(current_time, last_dma_callback_time)
    pthread_mutex_unlock(&freeze_detect_timer_mutex); 
    
    /* periodically check lapsed time since last DMA callback:
     * CSIRX_DMA_CALLBACK_TIMEOUT can be several frame durations, e.g. 16.66msec * 5
     * for 5 frames at 60fps
    */
    if(it is time to check DMA call back timeout) {
        if( time_elapsed > CSIRX_DMA_CALLBACK_TIMEOUT) {
            // CSI DMA call back time out, streaming likely frozen, take action
        }
    }

Regards,

Jianzhong