Hello, on a custom board based on imx6ul once linux starts I see lot of errors like this: caam_jr 2141000.jr: 2000005b: CCB: desc idx 0: RNG: Hardware error approximately every 10 seconds. And if I try to read from device the same error occurs: ~# dd if=/dev/hwrng of=/dev/null bs=1 count=1 caam_jr 2141000.jr: 2000005b: CCB: desc idx 0: RNG: Hardware error dd: /dev/hwrng: Invalid argument No errors are fired in barebox where the RNG self-test is run succesfully: rng_self_test: RNG software self-test passed caam 2140000.crypto@xxxxxxxxxx: Instantiated RNG4 SH0 caam 2140000.crypto@xxxxxxxxxx: Instantiated RNG4 SH1 caam 2140000.crypto@xxxxxxxxxx: registering rng-caam Here [1] I found that enlarging the entroy delay may help so I tried to do the same in barebox by changing RTSDCTL_ENT_DLY_MIN from 3200 to 4800 and it succeded, I no longer see those errors in linux and trying to read from the device works perfectly. The strange thing is that on another board based on imx6sx I never see those errors. Is it something new to you? May we change the delay? On linux-imx 6.6.3 3200 is still used. Best, Stefano [1] https://lore.kernel.org/all/CAOMZO5D0m1xCfgFifKz1H+oYQSfxsfuZp4U39rPMACmzv1fvjQ@xxxxxxxxxxxxxx/#t
