CPU frequency scaling driver for mvebu (WRT3200ACM etc.)

smj · March 19, 2019, 6:36pm

I certainly would be really keen on seeing this - it's quite crazy how hot the WRT3200ACM runs when it can't frequency scale.

neheb · March 20, 2019, 1:38am

Might need some liquid metal

ParanoidZoid · March 20, 2019, 3:12pm

Can you point to us where the new non-broken parts are? Their branching/versioning system is a mess to navigate. However, from what I gather, it seems that CPU Idle and CPU Hotplug are still disabled within the arch/arm/mach-mvebu/pmsu.c file.

Within the 4.14.76-armada- 18.12 branch these still exist:

github.com

MarvellEmbeddedProcessors/linux-marvell/blob/97af2232d911e2132c05d1d1a1b9eff10f9a3b1e/arch/arm/mach-mvebu/pmsu.c#L431-L432


	pr_warn("CPU idle is currently broken on Armada 38x: disabling\n");
	return 0;

github.com

MarvellEmbeddedProcessors/linux-marvell/blob/97af2232d911e2132c05d1d1a1b9eff10f9a3b1e/arch/arm/mach-mvebu/pmsu.c#L505-L512


	 * Currently the CPU idle support for Armada 38x is broken, as
	 * the CPU hotplug uses some of the CPU idle functions it is
	 * broken too, so let's disable it
	 */
	if (of_machine_is_compatible("marvell,armada380")) {
		cpu_hotplug_disable();
		pr_warn("CPU hotplug support is currently broken on Armada 38x: disabling\n");
	}

This same code still exists on Marvell's most recently updated branch on their other kernel repo here: https://github.com/MarvellEmbeddedProcessors/mainline-public/blob/mc/net-next/ppv2-cos/arch/arm/mach-mvebu/pmsu.c

This code came from this patch. The bug is in the hardware (though he was wrong about the XP not having this problem given the 1900ACv1 random reboot fiasco we had a year ago).

tiagogaspar8 · March 20, 2019, 4:30pm

I remember I saw one that had no "boken" part in it but I lost it... Oh well, I made a goof, sorry for the confusion.
I have to say I'm rather disappointed that this'll never be fixed. I mean, it doesn't spend that much energy and it's a pretty awesome router, but it's still annoying, some of the open source parts of this router are really missing, there are a lot of unused hardware features missing but what can you do ahahha.
Just one last question, you mentioned that CPU hotplug and Idle are disabled because of the hardware malfunction, but what about the frequency scaling? Is it related too?

Thanks for the help!

anon43989622 · May 28, 2020, 7:04am

Just got me a 3200 however it runs cinda hot, is this still a dead end with cpu scaling?

jeff1 · May 28, 2020, 7:35am

I use it on my WRT32x , has been working well for me , on kernel 5.4 -10 degrees when compared with kernel 4.14.

smj · May 28, 2020, 7:43am

Yeah it’s just a shame it has to run so hot because of this

anon43989622 · May 28, 2020, 8:09am

oh that´s nice, is there a build or do i have to compile it myself?

hnyman · May 28, 2020, 8:27am

Best is if you compile it by yourself, so that you get just the packages that you want. The patches are above.

But I have also semi-regularly updated my own build, mentioned early in the thread:

download link:

IceG · May 30, 2020, 1:18pm

Hi
Is there a chance for a patch for kernel 5.4.42?

anomeome · May 30, 2020, 5:15pm

sed -i 's/patches-4.19/patches-5.4/g' 419scaleCPUFreq.patch

solidus1983 · May 31, 2020, 4:06am

Running Kernel on 5.4.42 with @anomeome command to update the patch and it seems to run perfectly fine on the WRT32X just wondering either @anomeome @hnyman or @jeff1 has any suggestions for the CPU governor setup?

PerkelSimon · May 31, 2020, 11:24am

I thought your builds were only for r7800, nice to know, I have both. wrt3200 and r7800

currently I use davidc502 build on the last kernel, don't know if I can use the patch about high temp?

Or I need to update with your build?, if so, I can update directly from davidc to yours?

thanks

PerkelSimon · May 31, 2020, 5:36pm

How you install the patch?
I have the same kernel but davidc502 build

hnyman · May 31, 2020, 5:38pm

You download or edit the patch into your local sources, and then you compile the firmware. If you place the patches correctly to the mvebu kernel patches directory, it will get taken into account in the kernel compilation.

PerkelSimon · May 31, 2020, 5:56pm

Ok.
Even if you explain me that in Chinese I will try

solidus1983 · May 31, 2020, 6:06pm

Yes I downloaded the 4.19 patch and then ran the command @anomeome put up after renaming the patch file to match. But I do self compile my firmware based on DavidC's setup.

PerkelSimon · May 31, 2020, 7:56pm

do i need to go somewhere here?

Sans titre

solidus1983 · May 31, 2020, 9:00pm

The patch file is for compiling the firmware from source. You don't place patch files on router.

If my personal builds was not internal i would of uploaded my build.
Not sure on Linksys devices if we can simply replace the kernel or not.

shm0 · June 1, 2020, 4:30am

With kernel 5.4 I get:
mvebu-pmsu: Cannot get clock for CPU 0
And no files are created in:
/sys/devices/system/cpu/cpu*/cpufreq/

Did I miss something?