media: rockchip-vpu: I should place the huffman table at kernel or userspace ?

Randy Li at
Mon Sep 26 20:43:35 PDT 2016

   I have just done a JPEG HW encoder for the RK3288. I have been told 
that I can't use the standard way to generate huffman table, the VPU 
supports only 10 levels with a different huffman table.
   If I send the huffman table through the v4l2 extra control, the 
memory copy is requested, although the data is not very large(2 x 64 
bytes) but still a overhead. The other way is to place them in the 
kernel driver, and just define the quality every time it encode a 
picture. But storing in kernel would make the driver a little bigger(2 x 
11 x 64 bytes) and beyond the FIFO job.
   So where Should I place the huffman table?
Randy Li
The third produce department
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