When transferring a small amount of data, the DMA data will be wrong

[byheng]

Problem

When I was testing axidma_transfer.c, I prepared my test file 1.txt, which contained very little content, only two words "hello world". After I ran the command ./axidma_transfer 1.txt 2.txt, I used the command cat 2.txt to view the file content of 2.txt, and the result was blank.

Then I observed the data of M_AXIS_MM2S and S_AXIS_S2MM of dma in Syetem ila, and then I found that the data of TDATA did not correspond to the content of the sent file 1.txt at all.

But when I use axidma_transfer.c as the input file,and ran the command ./axidma_transfer axidma_transfer.c 2.txt the data of TDADA in DMA is correctly corresponding to axidma_transfer.c

my block design

waveform of test ./axidma_transfer 1.txt 2.txt, and only "hello world" in 1.txt

waveform of test ./axidma_transfer axidma_transfer.c 2.txt