Rtfs sata example sometimes succeed but sometimes fail?

Hello everybody:

I use the RTFS system to read and write SATA on the OMAP-L138 board. And I use bios_5_41_13_42, rtfs_1_10_02_32, pspdrivers_01_30_01.

I just import the example in ti\rtfs_1_10_02_32\packages\ti\rtfs\examples\sata\bios5\evm6748\ccs4. In most cases It failed and it stucked in the ATA_SubmitIdentify(). function, actually it stucked in m_delay(1u) function. But if I shake the interface of sata disk, sometimes the program can run successfully. And it could print all information I need.

So why is there such a phenomenon？What‘s the key problem?

Best wishes!

Regards

Samantha