Kernel log during first test: echo A > /dev/ttymxc4

kernel_log_1.txt

[   52.193765] mxs-dma 110000.dma-apbh: private_candidate: wrong capabilities
[   52.193782] imx-sdma 20ec000.sdma: private_candidate: dma1chan0 busy
[   52.193794] imx-sdma 20ec000.sdma: private_candidate: dma1chan1 busy
[   52.193968] dmaengine: __dma_request_channel: success (dma1chan2)
[   52.193987] imx-sdma 20ec000.sdma: load_address = 6722
[   52.193997] imx-sdma 20ec000.sdma: wml = 0x00000008
[   52.194007] imx-sdma 20ec000.sdma: shp_addr = 0x021f4000
[   52.194017] imx-sdma 20ec000.sdma: per_addr = 0x00000000
[   52.194025] imx-sdma 20ec000.sdma: event_mask0 = 0x00000000
[   52.194034] imx-sdma 20ec000.sdma: event_mask1 = 0x00000002
[   52.194115] mxs-dma 110000.dma-apbh: private_candidate: wrong capabilities
[   52.194126] imx-sdma 20ec000.sdma: private_candidate: dma1chan0 busy
[   52.194135] imx-sdma 20ec000.sdma: private_candidate: dma1chan1 busy
[   52.194144] imx-sdma 20ec000.sdma: private_candidate: dma1chan2 busy
[   52.194229] dmaengine: __dma_request_channel: success (dma1chan3)
[   52.194246] imx-sdma 20ec000.sdma: load_address = 747
[   52.194255] imx-sdma 20ec000.sdma: wml = 0x00000008
[   52.194263] imx-sdma 20ec000.sdma: shp_addr = 0x021f4040
[   52.194272] imx-sdma 20ec000.sdma: per_addr = 0x00000000
[   52.194280] imx-sdma 20ec000.sdma: event_mask0 = 0x00000000
[   52.194289] imx-sdma 20ec000.sdma: event_mask1 = 0x00000004
[   52.194620] imx-sdma 20ec000.sdma: setting up 1 entries for channel 4.
[   52.194633] imx-sdma 20ec000.sdma: load_address = 747
[   52.194641] imx-sdma 20ec000.sdma: wml = 0x00000008
[   52.194649] imx-sdma 20ec000.sdma: shp_addr = 0x021f4040
[   52.194657] imx-sdma 20ec000.sdma: per_addr = 0x00000000
[   52.194664] imx-sdma 20ec000.sdma: event_mask0 = 0x00000000
[   52.194673] imx-sdma 20ec000.sdma: event_mask1 = 0x00000004
[   52.194735] imx-sdma 20ec000.sdma: entry 0: count: 2 dma: 0x4c87d000  intr
[   52.194747] imx-uart 21f4000.serial: TX: prepare to send 2 bytes by DMA.
[   52.201979] imx-uart 21f4000.serial: we finish the TX DMA.
[   52.207618] imx-sdma 20ec000.sdma: setting up 2 entries for channel 4.
[   52.207629] imx-sdma 20ec000.sdma: load_address = 747
[   52.207637] imx-sdma 20ec000.sdma: wml = 0x00000008
[   52.207646] imx-sdma 20ec000.sdma: shp_addr = 0x021f4040
[   52.207654] imx-sdma 20ec000.sdma: per_addr = 0x00000000
[   52.207662] imx-sdma 20ec000.sdma: event_mask0 = 0x00000000
[   52.207669] imx-sdma 20ec000.sdma: event_mask1 = 0x00000004
[   52.207756] imx-sdma 20ec000.sdma: entry 0: count: 4092 dma: 0x4c87d004 
[   52.207769] imx-sdma 20ec000.sdma: entry 1: count: 2 dma: 0x4c87d000  intr
[   52.207781] imx-uart 21f4000.serial: TX: prepare to send 4094 bytes by DMA.
[   56.494124] imx-uart 21f4000.serial: we finish the TX DMA.
[   56.499784] imx-sdma 20ec000.sdma: setting up 2 entries for channel 4.
[   56.499797] imx-sdma 20ec000.sdma: load_address = 747
[   56.499805] imx-sdma 20ec000.sdma: wml = 0x00000008
[   56.499823] imx-sdma 20ec000.sdma: shp_addr = 0x021f4040
[   56.499831] imx-sdma 20ec000.sdma: per_addr = 0x00000000
[   56.499838] imx-sdma 20ec000.sdma: event_mask0 = 0x00000000
[   56.499846] imx-sdma 20ec000.sdma: event_mask1 = 0x00000004
[   56.499869] imx-sdma 20ec000.sdma: entry 0: count: 4070 dma: 0x4c87d01a 
[   56.499879] imx-sdma 20ec000.sdma: entry 1: count: 2 dma: 0x4c87d000  intr
[   56.499889] imx-uart 21f4000.serial: TX: prepare to send 4072 bytes by DMA.
[   60.738304] imx-uart 21f4000.serial: we finish the TX DMA.