Date: Fri, 19 Mar 2021 13:52:35 -0700 From: Mark Millard <marklmi@yahoo.com> To: bob prohaska <fbsd@www.zefox.net> Cc: Klaus K??chemann <maciphone2@googlemail.com>, freebsd-arm <freebsd-arm@freebsd.org>, Diane Bruce <db@db.net> Subject: Re: RPI4 clock speeds and serial port ( temperatures idle and -j4 buildworld buildkernel ) Message-ID: <FDBC2E89-8473-4C3A-B12E-78821949FDDB@yahoo.com> In-Reply-To: <20210319195019.GA39087@www.zefox.net> References: <20210318170053.GA26688@www.zefox.net> <9FFA0A51-C0B7-4121-95CA-B98669809007@yahoo.com> <E4CF6642-CB70-4495-A865-05469953561C@yahoo.com> <EA6BE351-98F5-4446-BA4D-948F04EDFD3B@yahoo.com> <81AC0353-258C-41C3-86B1-C133E33D97E3@yahoo.com> <20210319174359.GA38899@www.zefox.net> <FA5A110A-4E7A-4381-BBE5-9B3022CA9008@googlemail.com> <20210319195019.GA39087@www.zefox.net>
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On 2021-Mar-19, at 12:50, bob prohaska <fbsd@www.zefox.net> wrote: > On Fri, Mar 19, 2021 at 08:07:36PM +0100, Klaus K??chemann wrote: >>=20 >>=20 >>> Am 19.03.2021 um 18:43 schrieb bob prohaska <fbsd@www.zefox.net>: >>>=20 >>>=20 >>> So my figures (~17 hours) seem reasonable for a default clocking. >>> I thought maybe I'd done something wrong. >>=20 >>=20 >> 17 hours sounds too long, you can simply enable ???powerd??? in = rc.conf for automatically=20 >> scaling from idle 600 to max. 1500 (non overclocked). >> So, when you hit make -j4 xyz, you will see all cpus running @~100% = and=20 >> Powerd will then automatically set the clock speed to 1500 on all 4.=20= >>=20 >=20 > I've enabled powerd and rebooted, console messages report that powerd > started with no explicit errors. A -j4 buildworld is running now. >=20 > Should I expect to see powerd mess up the default mini-uart serial = console? > So far, it hasn't with top reporting less than 1% idle. That's = confusing.... Avoid confusing the arm_freq with the core_freq (core is VPU, not arm). The two are independent (up to the RPi* firmware's dynamic frequency clocking logic anyway). I've already reported that the documentation indicates that the core_freq is not supposed to be changed on the RPi4's. (The use or not of 2 features controls the exact value that it must be and the firmware appearently already deals with tracking those: hdmi_enable_4kp60 and enable_tvout .) https://www.raspberrypi.org/documentation/configuration/uart.md reports that the mini UART is tied to the core_freq, not the arm_freq. So on a RPi4B where hdmi_enable_4kp60 and enable_tvout are not changing, the core_freq assignment should also not be changing, no matter what arm_freq changes are being made. That leaves core_freq_min for the RPi* firmware's dynamic frequency clocking. The default is 250 or 275, apparently depending on the status of hdmi_enable_4kp60, 275=3D550/2, when hdmi_enable_4kp60 is enabled, otherwise 250 is used (for the core_freq 500 and 360 cases). [The 360 (enable_tvout) case is not well documented for core_freq_min .] It is not clear when the dynamic frequency clocking logic would adjust the actual core frequency but it appears that the official way to avoid messing up the mini UART is to assign: core_freq_min to match the value of the core_freq setting so that no other setting is available. If the mini UART is working in your context and you have not disabled Bluetooth or redirected the UART Bluetooth is using, what I infer is that the RPi* firmware's dynamic frequency clocking happens to not be adjusting the live core_freq significantly in your context. Also of note . . . QUOTE Pi 4 - six UARTS The Raspberry Pi 4 has four additional PL011s, which are disabled by = default. The full list of UARTs on the Pi 4 is: Name Type UART0 PL011 UART1 mini UART UART2 PL011 UART3 PL011 UART4 PL011 UART5 PL011 END QUOTE =3D=3D=3D Mark Millard marklmi at yahoo.com ( dsl-only.net went away in early 2018-Mar)
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