i.MX ProcessorsのトピックRe: imx6q CPU thermal sensor wrong?

imx6q CPU thermal sensor wrong?

chuanyanyin — Fri, 21 Mar 2014 08:38:03 GMT

When I run ott with android 4.0.4, the kernel always report "Chip is too hot ...." , And I got wrong cpu temperature "Invalid temperature, force it to 25C"

Thermal calibration data is 0x4e67d, cpu info is

cpuinfo

Processor : ARMv7 Processor rev 10 (v7l)

processor : 0

BogoMIPS : 1988.29

processor : 1

BogoMIPS : 1988.29

processor : 2

BogoMIPS : 1988.29

processor : 3

BogoMIPS : 1988.29

Features : swp half thumb fastmult vfp edsp neon vfpv3

CPU implementer : 0x41

CPU architecture: 7

CPU variant : 0x2

CPU part : 0xc09

CPU revision : 10

Hardware : Freescale i.MX 6Quad/DualLite OTT TV BOX Board

Revision : 63011

Serial : a265d1d4d72d7819

Is the mx6 burn with wrong Thermal calibration data?

Re: imx6q CPU thermal sensor wrong?

Chris1z — Fri, 21 Mar 2014 13:27:57 GMT

4.0.4 is pretty old. You will want to go look in the 4.3.1-1.1.0-ga branch or something newer. There are changes to the kernel and u-boot to use a global thermal equation (instead of the inaccurate calibration values stored in the fuses). Look in these files:

kernel:

drivers/mxc/thermal/thermal.c

u-boot:

cpu/arm_cortexa8/mx6/generic.c

With that said, you still may see these thermal warning with these patches if your design is not well ventilated or has a heat sink. Once you have those patches, you can also monitor the iMX6 thermal sensor by using these sysfs:

# turn on thermal log (print to console every two seconds)

echo 2 > /sys/module/thermal/parameters/debug_mask

# turn off thermal log

echo 0 > /sys/module/thermal/parameters/debug_mask

# print out current temp once

cat /sys/class/thermal/thermal_zone0/temp