How to use multiple dma channels for data transmission at the same time in Jetson Xavier?

Hello everyone,

We have configured the Jetson AGX Xavier board as an endpoint and tried to transfer data from endpoint to root complex using endpoint dma channels. We are transferring video frames from endpoint to root complex.

When we transferred video frames from endpoint using dma channels , by using one channel at a time, it worked fine and data transferred without any issue. But, when we tried to transfer frames in multiple channels at the same time using thread function, the frames are getting transferred only through channel_0 and frames are not getting transferred in other channels.

While transferring frames in one channel, if we change the channel number in DMA_WRITE_DOORBELL_OFF, will the transfer of data happens through both the channels or the latest one? If the transfer will happen only in one channel, how can I use multiple channel at the same time for transferring frames?