CPU scaling frequency somehow limited to about 2.0 GHz

Autonomous Machines Jetson & Embedded Systems Jetson TK1
1

I have a Jetson TK1 that I just flashed with L4T 21.5.

I’m trying to follow this guide to maximize the performance of the TK1: http://elinux.org/Jetson/Performance

The guide and numerous other online sources say that the Jetson TK1 can go up to 2.3 GHz.

Indeed, I have another Jetson TK1 that I have setup with L4T 21.4 a long time ago, and this is what I see on that device:

$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies
51000 102000 204000 312000 564000 696000 828000 960000 1092000 1122000 1224000 1326000 1428000 1530000 1632000 1734000 1836000 1938000 2014500 2116500 2218500 2320500

Note that the numbers are expressed as kHz.

However, on this device that I just setup with L4T 21.5, this is what I see:

$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies
51000 102000 204000 312000 564000 696000 828000 960000 1092000 1122000 1224000 1326000 1428000 1530000 1632000 1734000 1836000 1887000 1938000 1963500 2065500

So I’m somehow limited to ~2.0 GHz.

Does anybody know what’s going on and how I can fix that? I want the full 2.3 GHz.

2

I think I have found my answer:

According to the release announcement:

Section 3.2 of the release notes also mentions the same thing: http://developer.download.nvidia.com/embedded/L4T/r21_Release_v5.0/Docs/Tegra_Linux_Driver_Package_Release_Notes_R21.5.pdf?autho=1482390902_5dd38e8dd567762e241b0b512ef67b3b&file=Tegra_Linux_Driver_Package_Release_Notes_R21.5.pdf

However, neither places say exactly what the new CPU speed limit is.

Is there a way to unlock the higher CPU clock and voltage even on L4T 21.5? I really want the full 2.3 GHz.

Honestly, why doesn’t nVidia just change the default value in /sys/devices/system/cpu/cpu*/cpufreq/scaling_max_freq?

3

Hi k_sze,

The CPU Frequency specs were updated to ensure reliable operation over the lifetime of the product and cannot be changed. The latest specs can be found in the product datasheet:

[url]http://developer.nvidia.com/embedded/dlc/tegra-k1-datasheet[/url]

Thanks