DMA Allocation Issue with TW6865 Chip

[ranaya123]

With the new patches of tw686x applied to the kernel 4.1.15.2, following error (or warning) appears when running gstreamer-1.0 with tw6865 chip.

v4l2bufferpool gstv4l2bufferpool.c:748:gst_v4l2_buffer_pool_start: Uncertain or not enough buffers, enabling copy threshold

Moreover in dmesg, I can see following error being repeated when streaming starts : unexpected p-b buffer

I can clearly see the images in eglvivsink window. But image capturing is pretty slow and in certain occasions, the whole system hangs. I also tried increasing cma and coherent_pool sizes, but issue remains same ! Also set the gpumem=67108864 ! what could cause this "not enough buffers" issue ?

[tkisky]

On 2/23/2017 8:45 AM, ranaya123 wrote:

With the new patches of tw686x applied to the kernel 4.1.15.2, following error appears when running gstreamer-1.0 with tw6865 chip.

v4l2bufferpool gstv4l2bufferpool.c:748:gst_v4l2_buffer_pool_start:v4l2src0:pool:src Uncertain or not enough buffers, enabling copy threshold

I can clearly see the images in eglvivsink window. But image capturing is pretty slow and in certain occasions, the whole system hangs. I also tried increasing cma and coherent_pool sizes, but issue remains same ! Also set the gpumem=67108864 ! what could cause this "not enough buffers" issue ?

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CMA is increased via devicetree in 4.1. I don't think changing the command line will have any effect unless the cma dt node is completely removed.

• reserved-memory {
• linux,cma {
• size = <0x20000000>;
• };

[ranaya123]

I accidentally pressed the issue close button, sorry for that. I tried changing the cma size in both ways (while removing the node from dts), but it didn't improve the fps. For fpsdisplaysink I am only getting an average of 2 f/s.
gst-launch-1.0 -v v4l2src device=/dev/video1 ! fpsdisplaysink video-sink=fakesink text-overlay=false

Moreover unexpected p-b buffer and not enough buffers errors seem to be recurrent ! what else should be in my checklist ? Thanks

PS : do we need a similar patch to the one given by you in following post ? I am using Nitrogen6_max board ! https://community.nxp.com/thread/304368

[gibsson]

Hi,

Please check if this crash still occurs with latest 4.1.15_2.0.0 revision: https://github.com/boundarydevices/linux-imx6/commit/511c42e

Regards, Gary

[gibsson]

Hi,

Since we haven't heard back for a long time, we consider this issue fixed.

Regards, Gary

[ranaya123]

Hello Gary, I moved to tw6869 driver instead and the video just worked fine. But I'll certainly note the change.

Thanks Anuradha