Re: kern/57564 raspberry pi zero W also panic in linux (tried cpu freq reduction)

[Ramiro Aceves <ea1abz%gmail.com@localhost>]

The following reply was made to PR port-evbarm/57564; it has been noted by GNATS.

From: Ramiro Aceves <ea1abz%gmail.com@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: port-arm%netbsd.org@localhost, port-evbarm-maintainer%netbsd.org@localhost,
 Taylor R Campbell <riastradh%NetBSD.org@localhost>, netbsd-bugs%netbsd.org@localhost
Subject: Re: kern/57564 raspberry pi zero W also panic in linux (tried cpu
 freq reduction)
Date: Sat, 9 Sep 2023 13:49:39 +0200

 Hello,
 
 I have been investigating crashes under raspbian Debian GNU/Linux for 
 several days and found in internet that Raspberrypi Zero W frequently 
 panices with CPU max frequency set to 1 GHz.
 
 As I told before, I have got crashes after several hours of the CVS and 
 rm -rf pkgsrc torture test in such conditions.
 
 I found internet articles that suggested reducing max CPU frequency from 
 1 GHz to the next scaling step, 900 MHz. After doing that, I have run 
 the test for 3 days and no panics at all. At the end, SD card showed a 
 problem and system went suddenly read only. I copied the SD into a file 
 for further investigation.
 
 After that, I started to burn NetBSD 10 beta on the SD card but it 
 refused to be written. SD card was dead, I could not flash it with any 
 computer at home.
 
 I have just bought a new card, this time 64 GB size (last one was 16GB). 
 I have flashed my NetBSD 10 beta copy from the backups with the custom 
 kernel with Taylor modification. It automagically resized to the full 64 
 GB of the card at the first boot.
 
 It showed the following CPU available frequencies. I do not know why but 
 900 MHz is not available:
 
 machdep.cpu.frequency.available = 700 1000
 
 So I set in /etc/rc.local:
 
 sysctl -w machdep.cpu.frequency.target=700
 
 Now raspberrypi Zero W is running at 700 MHz:
 
 sysctl -w machdep.cpu.frequency.target=700
 raspa-netbsd$ sysctl -a | grep freq
 machdep.cpu.frequency.target = 700
 machdep.cpu.frequency.current = 700
 machdep.cpu.frequency.min = 700
 machdep.cpu.frequency.max = 1000
 machdep.cpu.frequency.available = 700 1000
 
 I am running the CVS/rm torture test. We'll see what happens.
 
 Regards.
 Ramiro.