Hello Fabio, Peng, I have here an imx6ull based board from DH electronics [1] which has the IMX_THERMAL driver enabled in U-Boot and Linux. We see on Linux boot random crashes (random means not on every boot, also not even the same crash dump/reason in linux). My first suggestion was instable RMA, but RAM seems stable.
After some investigation it turned out, that setting the REFTOP_SELBIASOFF bit in the linux thermal driver seems the problem. I saw that the kernel driver does not check first if REFTOP_VBGUP is set and added this, but this did not helped. U-Boot does this check here: https://gitlab.denx.de/u-boot/u-boot/blob/master/arch/arm/mach-imx/mx6/soc.c#L342 More investigation into this problem and we found how U-Boot handles this bit: U-Boot: sets this bit in arch_cpu_init() U-Boot: sets this bit in IMX_THERMAL driver U-Boot: clears this bit in IMX_THERMAL driver If we now remove the clearing of this bit in U-Boot in the thermal driver, we also see no crashes anymore in Linux (more than 12000 power on/off cycles) My question is now, - do you now more about this bit as in the RM is described? Or know somebody we can ask? - What effect has this bit? May it leads in more power consumption? - Is it valid to not clear it in U-Boot? Thanks in advance! bye, Heiko [1] https://github.com/dh-electronics/u-boot-imx6qdl/blob/dev/2018.05_dhcom/include/configs/dh_imx6ull.h -- DENX Software Engineering GmbH, Managing Director: Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: +49-8142-66989-52 Fax: +49-8142-66989-80 Email: h...@denx.de
