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what‘s meaning of SEM: post _TSK_mutex？

xiansheng shao
Prodigy 240 points

Hi.

My env is DM6467T + CCS4.1 + DSP/BIOS 5.41 + XDAIS 6.25 + codec_engine_2_10_01+ dm6467_h264dec_1_10_05_03_production + dm6467_hdvicp_1_01_020_production.

I create a simple project in ccs4.1with DSP/BIOS 5.41 for run the h264decode function use the HDVICP of DM6467T.

But when i decode one frame i found that the CLK_F_isr() function cannot be called (when i don't call the decode function the CLK_F_isr() can be called). So all the timeout function of DSP/BIOS API don't have effect, such as TSK_sleep(10) and so on. In the ROV of DSP/BIOS 5.41, I found the message "SEM: post _TSK_mutex"  in LOG_system modules. So my question is what's the meaning of SEM: post _TSK_mutex, and why the CLK_F_isr() can not be called(that means  system clock cannot drived by the Timer0 or Timer1 in DM6467T)?

I found that  have post some info about the TSK_mutex (http://e2e.ti.com/support/dsp/tms320c6000_high_performance_dsps/f/115/p/53363/759179.aspx) , but i want to know the details.

Thanks.

Shao.

  • 0
    TI__Mastermind 30830 points

    The runtime support libraries provided by the compiler tools have 'lock' and 'unlock' hook functions that are called within some of the library APIs to protect against re-entrancy issues.

    These hook functions are there so that the user can insert application-specific functions that ensure thread safety.

    BIOS installs its own "lock" and "unlock" functions that utilize an internal SEM object called "_TSK_mutex" to ensure thread safety.

    The lock function calls SEM_pend(_TSK_mutex, SYS_FOREVER) and the unlock function calls SEM_post(_TSK_mutex).

    Each time a runtime support library API that utilizes the lock and unlock feature is invoked, you will see a corresponding SEM_pend() and SEM_post() log entry.

    Alan

  • 0 in reply to Alan DeMars
    Prodigy 240 points

    Thanks for your replay.

    I don't use the SEM_post(_TSK_mutex) in my program, so i guess the SEM_post(_tsk_mutex) called by the lib in my program. I use the HDVICP lib to decode H264 stream in dm6467t. I want to know how to stop the SEM_post(_TSK_mutex), because i don't know which function run SEM_post(_TSK_mutex). You can found in the last post pic that there is not CLK info in my task, that means the TIMER0 of system lost effect, and the timeout of DSP/BIOS API lost effect.

    Thanks.

  • 0 in reply to xiansheng shao
    TI__Mastermind 30830 points

    I believe that the calls to SEM_post() in your application are coming from an IDL function that periodically invokes C library functions for performing HOST I/O to exchange RTA data between CCS and the target processor.

    This IDL function is part of the target/host logging mechanism which drives the LOG module ROV view you show in your post.

    The C library function calls the lock() and unlock() APIs I described above.

    Apparently only the SEM_post() call is being logged.

    Alan

  • 0 in reply to Alan DeMars
    Prodigy 240 points

    Thank you for your replays.

    You are correct, I found the SEM_post send by the RTA module.

    Thanks a lot.