frmbuf write "xilinx-video amba_pl@0:video_cap_my: dma_alloc_coherent of size 0 failed"

[lrocher]

hi,

i make a design that read a data from the ddr with a vdma and i send data to frame buffer

on linux when i configure V4L2 :

 v4l2-ctl --device /dev/video0 --set-fmt-video=width=1920,height=1080,pixelformat=RGB8

it works but when i want to make a capture with this command :

v4l2-ctl --device /dev/video0 --stream-mmap --stream-skip=1 --stream-to=frame.raw --stream-count=1

i have a kernel crach :

[ 26.492932] xilinx-video amba_pl@0:video_cap_my: dma_alloc_coherent of size 0 failed
[ 26.500619] Unable to handle kernel NULL pointer dereference at virtual address 00000000
[ 26.508674] Mem abort info:
[ 26.511442] Exception class = IABT (current EL), IL = 32 bits
[ 26.517354] SET = 0, FnV = 0
[ 26.520383] EA = 0, S1PTW = 0

do you have an idea ?

thanks

[florentw]

Hi @lrocher,

Why are you using a VDMA? Why not doing both write and read with a frame buffer. This way your full pipe should be suported by V4L2 while I am not sure the VMDA supports the V4L2 framework.

Regards,

[florentw · Accepted solution]

HI @lrocher,

Do you have any updates on this?

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Thanks and Regards,