HWBOT Prime Benchmark Script 2.0

Table of contents

The Update

This week I changed the process of identification inside my little HWBOT Prime1 benchmark script, about which I wrote a blog some time ago.
The main purpose is to collect as much and correct information in order to provide this data for uploading the benchmark score, so the part to identify the used Raspberry Pi is very important.

I rewrote the whole part and used the unique revision code of each RPi, which is stored inside /proc/cpuinfo.

If you see this, the image is broken :(

Revision Codes

Every Raspberry Pi model has its own revision code which is unique.
On the official website2 you can find a table which model has which revision code. I used this table and added some more information about SoC, CPU etc.

Now, you get these information:

While comparing the revision codes from my different RPi-models with the ones provided by the official documentation, I found a flaw inside the current OS and an outdated documentation.
The documentation says there are two code styles, an old 4-digit hex-code for the Raspberry Pi 1 and a new 6-digit one for Raspberry Pi 2 and above.
Unfortunatelly none of my old RPi1s have an old-style revision code, but an odd 7-digit one. You get a 100000e instead of a 000e. My RPi2B and 3B (but not 3B+) also have this 7-digit code, but with a 2 as prefix to its normal new-style revision code.

Here you can see the different patterns of revision codes:

Model Rev Code (documentation) Rev Code (read out)
Raspberry Pi Model B Rev 2 / 512 MB 000e 100000e
Raspberry Pi Model B+ Rev 1.2 / 512 MB 900032 1900032
Raspberry Pi 2 Model B Rev 1.1 / 1 GB a01041 2a01041
Raspberry Pi 3 Model B Rev 1.2 / 1 GB a02082 2a02082
Raspberry Pi 3 Model B+ Rev 1.3 / 1 GB a020d3 a020d3
Raspberry Pi 4 Model B Rev 1.1 / 1 GB a03111 a03111
Raspberry Pi Compute Module 4 Rev 1.0 / 1 GB a03140 a03140

I filed issue #1888 at the official GitHub repository.
Maybe the behaviour is right, but the documentation is simply outdated, maybe it’s a bug.

Update: 29.04.2021

Issue #1888 was closed and now I’m wiser than before.
I misunderstand the way the revision code is generated…and there is a little flaw the RPi does it.

The new-style revision code is a result of a 32 bit value, (almost) each bit represents a piece of hardware-information: NOQuuuWuFMMMCCCCPPPPTTTTTTTTRRRR

Overvoltage OTP Program OTP Read Unused Warranty bit Unused New flag Memory size Manufacturer Processor Type Revision

The prefixed 1 for the Raspberry Pi 1s a result of the warranty bit set to 1, due to overclocking. But the wrong bit in the pattern is used to indicate that the warranty is void.

Raspberry Pi Model B Rev. 2
100000e in hex means 1000000000000000000001110 in bin.

Raspberry Pi Model B+ Rev 1.2
1900032 in hex means 1100100000000000000110010 in bin.

Overvoltage OTP Program OTP Read Unused Warranty bit Unused New flag Memory size Manufacturer Processor Type Revision
0 0 0 000 0 1 0 000 0000 0000 00000000 1110
0 0 0 000 0 1 1 001 0000 0000 00000011 0010

As you can see, the warranty bit isn’t set to 1, but the unused bit between the warranty and the new flag bit. This is the flaw.
The correct revision code should be 200000e and 2900032.
For the Raspberry Pi 2 and 3 the 2 as a prefix indicates a voided warranty. Everything is normal.

Since the Raspberry Pi 3 B+ no warranty bit is set any more, because the Raspberry Pi Foundation saw no correlation with a set warranty bit and increased chip failures.

I’m currenty working on a new version of my script, to improve the collection of information across all RPi generations.
As always, I’ll keep you updated.

The script in action

The script checks the revision code stored in /proc/cpuinfo and compares it to the table.
Since I’m no programmer the task of comparing the read out code to the one stored in the table, was quite difficult. A good friend of mine introduced me to associative arrays.

I also tuned the look a little bit, so the information is displayed in a more satisfyingly order.

If you see this, the image is broken :(

You can download the script at my GitHub Gist.3

  1. HWBOT Prime Benchmark ↩︎

  2. Revision Codes ↩︎

  3. HWBOT Prime Benchmark Script ↩︎