iMX6 TW686x Surround view patch

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iMX6 TW686x Surround view patch

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iMX6 TW686x Surround view patch

We use PCIe to connect Intersil TW6865 chip for the surround view solution.

This is the connection of PCIe to iMX6Q SabreSD board.5171_5171.JPG1.JPG


This is the block diagram of the connection:


This is the 4 camera surround view:5173_5173.JPG4.JPG


Code base is L3.0.35_12.10.02 release. You can merge the patch file to the latest Freescale release.

Please check the attach file for the patch code.


Note:  It is only a test version.

The last code for L3.0.35 BSP: L3.0.35_GA4.1.0 Patches.7z

The last code for L3.10.53 BSP: L3.10.53_TW686x_patch.7z

Patch for L4.1.15 1.1.0 GA BSP: TW6865 driver for Linux L4.1.15_1.1.0-ga.7z

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Hi, is your intended video device enumerated ? i.e. what v4l2-ctl -d /dev/videox --all give you ? 

and try exactly this : 

gst-launch-1.0 -v v4l2src device=/dev/video0 ! video/x-raw,width=720,height=480,pixelformat=UYVY ! imxipuvideotransform ! imxeglvivsink

Note, for me pci MSI had to be disabled in order to get video frames !!!


Now it's working with " gst-launch-1.0 v4l2src device=/dev/video2 ! imxv4l2sink overlay-width=512 overlay-height=300 overlay-top=300 overlay-left=0 "

I don't know why imxv4l2src doesn't work.

"v4l2-ctl -d /dev/videox --all" outputs is here:

Driver Info (not using libv4l2):
Driver name : tw686x
Card type : tw6869
Bus info : PCI:0000:01:00.0
Driver version: 4.1.15
Capabilities : 0x85200001
Video Capture
Extended Pix Format
Device Capabilities
Device Caps : 0x05200001
Video Capture
Extended Pix Format
Priority: 2
Video input : 0 (Composite0: ok)
Video Standard = 0x0000b000
Format Video Capture:
Width/Height : 360/240
Pixel Format : 'YUYV'
Field : Interlaced
Bytes per Line: 720
Size Image : 172800
Colorspace : Broadcast NTSC/PAL (SMPTE170M/ITU601)
Flags :
Streaming Parameters Video Capture:
Capabilities : timeperframe
Frames per second: 30.000 (30/1)
Read buffers : 3

User Controls

brightness (int) : min=-128 max=127 step=1 default=0 value=0 flags=slider
contrast (int) : min=0 max=255 step=1 default=100 value=100 flags=slider
saturation (int) : min=0 max=255 step=1 default=128 value=128 flags=slider
hue (int) : min=-128 max=127 step=1 default=0 value=0 flags=slider
brightness (int) : min=-128 max=127 step=1 default=0 value=0 flags=slider
contrast (int) : min=0 max=255 step=1 default=100 value=100 flags=slider
saturation (int) : min=0 max=255 step=1 default=128 value=128 flags=slider
hue (int) : min=-128 max=127 step=1 default=0 value=0 flags=slider

If I use imxv4l2src, it will say "could not link imxv4l2src0 to imxv4l2sink0".

Hi, now can you get the video stream without any latency as expected ? Do you have a git link to the driver you use with sabresd ? Or are you using a different board ?


1. For now, I'm using only one camera, if I run two or more camera there will be some error message:

ERROR: from element /GstPipeline:pipeline0/GstV4l2Src:v4l2src0: Internal data flow error.
Additional debug info:
../../../../gstreamer-1.8.1/libs/gst/base/gstbasesrc.c(2948): gst_base_src_loop (): /GstPipeline:pipeline0/GstV4l2Src:v4l2src0:
streaming task paused, reason error (-5)

command is below:

gst-launch-1.0 v4l2src device=/dev/video0 ! imxv4l2sink overlay-width=512 overlay-height=300 overlay-top=0 overlay-left=0 &
gst-launch-1.0 v4l2src device=/dev/video1 ! imxv4l2sink overlay-width=512 overlay-height=300 overlay-top=0 overlay-left=512 &

For one camera, there is no latency.

2.  I use the driver you provided is another post, linux-imx6/drivers/media/pci/tw686x at boundary-imx_4.1.15_2.0.0_ga · boundarydevices/linux-imx6 · G... , I also try this one GitHub - sasamy/tw6869: tw6869/65 media bridge driver , same result.

I'm using a customed board.

I remember I had 'unexpected p-b buffer' issue while running the camera, but I was experimenting this on one of the Boundary Devices boards. Which board and distro are you using ? Can you also show the current memory map in kernel log?

i.e :- 

Memory: 3551600K/3932156K available (8196K kernel code, 314K rwdata, 2448K rodata, 1024K init, 444K bss, 52876K reserved, 327680K cma-reserved, 2260988K highmem)
Virtual kernel memory layout:
    vector  : 0xffff0000 - 0xffff1000   (   4 kB)
    fixmap  : 0xffc00000 - 0xfff00000   (3072 kB)
    vmalloc : 0xe6800000 - 0xff000000   ( 392 MB)
    lowmem  : 0x80000000 - 0xe6000000   (1632 MB)
    pkmap   : 0x7fe00000 - 0x80000000   (   2 MB)
    modules : 0x7f000000 - 0x7fe00000   (  14 MB)
      .text : 0x80008000 - 0x80b650ac   (11637 kB)
      .init : 0x80c00000 - 0x80d00000   (1024 kB)
      .data : 0x80d00000 - 0x80d4ea40   ( 315 kB)
       .bss : 0x80d51000 - 0x80dc0320   ( 445 kB)



My board is not belong to boundary boards.

yocto distro: "4.1.15-2.0.1", "fsl-imx-x11"

memory map:

Memory: 698176K/1048576K available (8364K kernel code, 432K rwdata, 3000K rodata, 432K init, 450K bss, 22720K reserved, 327680K cma-reserved, 0K highmem)

[ 0.000000] Virtual kernel memory layout:
vector : 0xffff0000 - 0xffff1000 ( 4 kB)
fixmap : 0xffc00000 - 0xfff00000 (3072 kB)
vmalloc : 0xc0800000 - 0xff000000 (1000 MB)
lowmem : 0x80000000 - 0xc0000000 (1024 MB)
pkmap : 0x7fe00000 - 0x80000000 ( 2 MB)
modules : 0x7f000000 - 0x7fe00000 ( 14 MB)
.text : 0x80008000 - 0x80b215e0 (11366 kB)
.init : 0x80b22000 - 0x80b8e000 ( 432 kB)
.data : 0x80b8e000 - 0x80bfa160 ( 433 kB)
.bss : 0x80bfd000 - 0x80c6d8c0 ( 451 kB)

I use the official kernel and use the boundary kernel's tw686x driver, I have also edited the quirk.c file.

Hi, have you got the issue resolved ? I can't see any issue in your logs. I also have the imxv4l2src video issue. I cannot even run a single camera consistently, the system freezes at a point and I am receiving 'unexpected p-b buffer issue' from the driver. I used Ubuntu for this. If there are any updates, please share with me !

I have not solved the imxv4l2src video issue.

The first thing is to make sure weather it is kernel's issue or gstreamer. Can you try nfs root? If so, it will be much convenient to try this rootfs:

rootfs.tar.bz2 - Google Drive , note it's for my linux 3.0.5, but it's also working for my linux 4.1.15 with device tree.

And then use 

gst-launch-0.10 v4l2src device=/dev/video0 ! 'video/x-raw-yuv, format=(fourcc)UYVY' ! mfw_isink disp-width=512 disp-height=300 axis-left=0 axis-top=0

test it.

Btw how can I add mfw_isink ? I have no such element in gst-inspect !

The command above only suitable to the gst-launch-0.10 in the rootfs I provide.

Hi Lei Ma,

Have you got the camera issue resolved with boundary devices driver ? I still have this latency and freezing issue. I am strictly following the data sheet schematic of tw6865 chip !


Sorry, I'm not familiar with linux device driver, for now I'm focus on image process with opengl es and opencv.

Boundary devices driver has two drivers for tw6865, one is tw6869 from GitHub - sasamy/tw6869: tw6869/65 media bridge driver  another is tw686x from upstream kernel, I use the upstream one. 

Hi, that's right. I am referring to the upstream kernel driver. Since you got it working without any problem I was wondering whether you have made a change to HW or Driver. In my case, for the upstream kernel driver, the video starts and frame rate becomes very low and then system hangs. I also see the 'unexpected p-b buffer' error in dmesg. Did you have to disable audio support or anything like that ? I had to disable pcie interrupt as well to get it work.... If you don't mind can you kindly share your linux .conf file ? I want to see kernel configurations under pcie. 



Here is my kernel config file, .config - Google Drive , I also disabled pcie interrupt.

Thanks very much Lei, this is very helpful. Btw do you see 'unexpected p-b buffer' error appears in dmesg when running the camera ?


No, there is no such error in my device.

Hi, thanks alot for the prompt repose. That confirms one thing to me, there is a problem in the driver or my hardware !


Hi, one last thing to confirm Lei, are you aware of following patch for dma allocation ? 

If you don't mind, can you kindly check or share videobuf-dma-contig.c or mxc_vpu.c files of your running kernel ? I saw in several posts, these changes are required. If you're not aware, I'd like to point this for your attention too.....


I don't know that, my kernel version is 4.1.15, and these two files is bit different.

videobuf-dma-contig.c - Google Drive  

mxc_vpu.c - Google Drive 

Hi Lei Ma,

I got to know from the original author of the driver that, imxv4l2videosrc only works for csi cameras. Not with this pci stuffs. So correct source is v4l2src ! 

Btw is your single camera working well for gst-launch-1.0 with imxv4l2sink as well ? Without any latency ? can you also show me your pci/quirks.c file ?

Kindly confirm me it .........


Sorry I forget this. Is "latency" means delay? If is there is no latency with my camera.

quirks.c - Google Drive 

Dear, Liqiang


We are using your patch( TW6865 driver for Linux L4.1.15_1.1.0-ga.7z)and trying to develop 4 camera surroundview application base on imx6d chip and PCIE\TW68x\ CVBS camera , but meet a problem!

The application always freeze at the following codes:


    if (ioctl(m_ifd, IPU_CHECK_TASK, &m_sTask) != IPU_CHECK_OK) {
        printf("IPU_CHECK_TASK failed.\r\n");
        return -1;


Do you know the reason? thanks a lot!




我们分配内存使用的接口是glTexDirectVIV, 而没有使用例子代码中的g2d_alloc;



是不是可以理解成这个patch( TW6865 driver for Linux L4.1.15_1.1.0-ga.7)中只支持VDI到g2d_alloc的空间,不支持VDI到malloc空间?


IPU task's input.paddr and output.paddr should be physical address of the input buffer and output buffer, if you use wrong address, it will fail to work.





Hi Qiang Li:

I use the IMX6Q core board. Now when using both GC2000 and GC320, there are occasional image tears on the screen display.
The specific implementation is like this:
   Get the real-time video data of the 4-way camera, display it on the GPU and display it in real time on the lvds screen. At the same time, the 4 channels of video are called by g2d to call the g2g_blit function for resize. The image of each frame is 720P resize to 640*480, and then synthesized into one frame. Image so that 4 channels of video can be displayed in one frame.the spliced video is not display on the screen and saved directly into the video,but now it is found that the video displayed by the GPU rendering in real time will be torn. Playback of the saved video also found that the image has a tearing problem, affecting the viewing effect.
   If you test the GPU rendering display separately, or the video of 4 channels of video is saved by G2D synthesis, there will be no image tearing problem.
But as long as these two functions are combined into one project, the problem of image tearing will occur when displaying and the saving  video.
1. Can I use the GC2000 of IMX6 and GC320 at the same time? Is there a problem with GPU resource preemption?
2. Is there a problem with data conflicts in the GPU? I have already made the GC2000 and GC320 get data that cannot be bufed, but after the two functions are integrated, there will still be a problem of video tearing.

I think you need check the delay for each processing step, before next processing, maybe the pre-step is not finished.





你的意思是说g2d_alloc 分配的不是连续物理内存吗?g2d_alloc 是如何分配内存的?



camera抓取图像,IPU task操作和G2D操作的源buffer和目标buffer都要求是物理连续内存。




另外,glTexDirectVIV 分配的内存是物理连续内存吗?谢谢

glTexDirectVIVMap()也可以得到物理连续内存,它的最后一个参数Physical可以用作IPU task操作和G2D操作的目标buffer。

According to what you mean, is the GC2000 and GC320 taking up the GPU in sequence? After the GC2000 has finished performing the on-screen rendering, can the GC320 take up GPU resources for 4-way image synthesis? Or first GC320 execution, then GC2000 re-execution? For different data buffers, can the two modules GC2000 and GC320 not run at the same time?

GC2000 and GC320 can run at the same time.






VPU可以同时编码分辨率时多少的4路视频?4个任务 同时使用VPU进行编码,不会有冲突吗?都会去抢占VPU的资源吧? 因为我使用IPU的时候可以创建4个任务,2个IPU,每个IPU内核中创建2个ipu_task,但是VPU也是有类似IPU的机制吗?不是很明确VPU的机制


我使用gstreamer进行4路视频编码为h264格式,使用让这个命令:srcapp->imxvideoconvert_ipu->vpuenc_h264->filesink, 我直接创建4 个pipeline就可以4路编码吗?系统会再VPU编码时自动处理每一路的编码顺序?

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