cpufreq driver stopped working on RPI4

[Mark Millard]

> On 2021-Feb-27, at 09:42, Mike Karels <mike at karels.net> wrote:
> 
> Following up on my previous post (below): I tried the ALPHA1 kernel on
> a BETA3 system on the RPI4, and it fails to attach the cpufreq driver
> as well.  So it appears that the problem is in the dtb, etc, not the
> kernel.
> 
> It would be nice to get this fixed before the 13.0 release.  Without
> the cpufreq driver, the CPU is stuck at a low clock rate.

In config.txt for an RPi4B I use (as an example, you
could use other figures):

over_voltage=6
arm_freq=2000
arm_freq_min=2000
sdram_freq_min=3200

and in /etc/sysctl.conf I have:

# The u-boot'ed RPi4B does not seem to automatically
# adjust from 600MHz, so do so manually. Presumes
# config.txt does over_voltage=6 and arm_freq=2000 .
# NOTE: without an appropriate over_voltage a
# dev.cpu.0.freq=2000 will crash the RPi4B on the
# spot.
dev.cpu.0.freq=2000

Overall this gives a constant faster frequency
for the CPU (and the sdram). (I have a good power
supply context for this.)

You may or may not be able to tolerate the constant
status for frequencies. But there is this alternative
to cpufreq use.


> 		Mike
> 
>> To: freebsd-arm at freebsd.org
>> From: Mike Karels <mike at karels.net>
>> Reply-to: mike at karels.net
>> Subject: cpufreq driver stopped working on RPI4
>> Date: Sun, 21 Feb 2021 14:43:27 -0600
> 
>> I upgraded an older (original) RPI4, 4 GB, to 13.0-BETA3, and merged my
>> previous rc.conf including powerd.  Powerd fails to start now, saying
>> that there is no cpufreq(4) support.  Sure enough, dmesg has the following
>> relevant lines:
> 
>>    bcm2835_cpufreq0: <CPU Frequency Control> on cpu0
>>    bcm2835_cpufreq0: Unable to find firmware device
>>    device_attach: bcm2835_cpufreq0 attach returned 6
>>    armv8crypto0: CPU lacks AES instructionsbcm2835_cpufreq0: <CPU Frequency Control> on cpu0
>>    bcm2835_cpufreq0: Unable to find firmware device
>>    device_attach: bcm2835_cpufreq0 attach returned 6
> 
>> (Yes, armv8crypto is missing a newline.)
> 
>> I checked the most recent system I had on the shelf, which was 13.0-ALPHA1.
>> It has this:
> 
>>    bcm2835_firmware0: <BCM2835 Firmware> on simplebus0
>>    ofw_clkbus1: <OFW clocks bus> on bcm2835_firmware0
>>    gpio0: <Raspberry Pi Firmware GPIO controller> on bcm2835_firmware0
>>    bcm2835_cpufreq0: <CPU Frequency Control> on cpu0
>>    bcm2835_cpufreq0: ARM 600MHz, Core 200MHz, SDRAM 400MHz, Turbo OFF
> 
>> Does anyone know what changed to cause this?  Was it the FDT update?
> 

===
Mark Millard
marklmi at yahoo.com
( dsl-only.net went
away in early 2018-Mar)