How to use system command safely in application based on DVRRDK?

SuitJune Young

Genius 3985 points

Hello,TIer.

now we found that if we use system command in application based on DVRRDK,the m3 video will be hang.

If we remove the system,m3 video will be normal.

Why does this happen?Could any TIer give me a hint?

0 Sivagamy Govindasamy over 11 years ago

Where are you trying to invoke system command & to do what? Please give more detail / code snippet.

0 SuitJune Young over 11 years ago in reply to Sivagamy Govindasamy

Genius 3985 points

No special command.

Just in Linux link_api process.

For example:

system("echo 0 > /sys/class/gpio/gpio_xxx/value);

If we execute system several times,the H.264 bitstream will not be generated randomly.

0 Badri Narayanan over 11 years ago in reply to SuitJune Young

There is an issue with doing "system" C library call after Syslink_setup is doen as system will do a fork and will end up with failure. Pls see this post: http://e2e.ti.com/support/dsp/davinci_digital_media_processors/f/717/p/247314/865280.aspx#865280

Avoid using system calls in your app. We have modified mcfw to avoid system calls. You can refer

/dvr_rdk/mcfw/interfaces/ti_vdis_timings.h Vdis_sysfsRead,Vdis_sysfsWrite functions for example usage.

If you have to use system, fork a process from your app befor doing Syslink_setup and issue all system calls from the other process.

0 SuitJune Young over 11 years ago in reply to Badri Narayanan

Genius 3985 points

Thanks very much for your detailed and deeply reply.

I know that.

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