CMSIS-DSP support seems broken on link

[mkvenkit]

Describe the bug

I am trying to use CMSIS-DSP in a simple project. I added the following to prj.conf:

CONFIG_CMSIS_DSP=y
CONFIG_NEWLIB_LIBC=y
CONFIG_FPU=y
# # Set CONFIG_NEWLIB_LIBC_FLOAT_PRINTF if  printf should be able to print float
CONFIG_NEWLIB_LIBC_FLOAT_PRINTF=y

In my code I am using:

#include "arm_math.h"
#include "arm_const_structs.h"
...

arm_rfft_fast_f32(&S, testInput, testOutput, 0);

This results in a linker error:

undefined reference to `arm_rfft_fast_f32'

As a workaround, I downloaded CMSIS_5 repo and modified CMakeLists.txt to include the necessary files.

Environment (please complete the following information):

• Linux
• Zephyr 2.5.0-rc3
• nRF52840-DK

[galak]

Did you also enable CONFIG_CMSIS_DSP_TRANSFORM=y ?

[mkvenkit]

That fixes the issue, thanks. But is this documented anywhere?

[galak]

That fixes the issue, thanks. But is this documented anywhere?

Kinda in the Kconfig help for CMSIS_DSP.