Date: Thu, 18 Mar 2021 18:43:17 +0000 From: tech-lists <tech-lists@zyxst.net> To: freebsd-arm@freebsd.org Subject: Re: RPI4 clock speeds and serial port Message-ID: <YFOfRfx29XUbgD33@ceres.zyxst.net> In-Reply-To: <20210318180736.GA26853@www.zefox.net> References: <20210318170053.GA26688@www.zefox.net> <YFONu3Ry0o6VlV92@ceres.zyxst.net> <20210318180736.GA26853@www.zefox.net>
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--c0mFzSTqqElW16HK Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Mar 18, 2021 at 11:07:36AM -0700, bob prohaska wrote: > >72 C is rather toasty 8-) it is, but it's been running like this fine for months. The machine also builds some 500 ports with poudriere. It's never throttled down due to heat; the ability to do this is I think outside of freebsd itself. Importantly [1] for me, the speed isn't nailed up with a boost statement in config.txt, so it can throttle back should the need arise. >Maybe on FreeBSD it doesn't matter. Pi-related sites report that the >mini-UART baudrate is tied to the clock of the GPU, if that changes >the baudrate changes too. It wasn't clear to me if the speed-changes to >config.txt affected the GPU clock. Apparently not, at least in FreeBSD. The cable I used was a FTDI usb <> tty cable; it has endings=20 that go over pins on the gpio. The FTDI chip in the usb end of the cable=20 handles the speeds (i think/not sure) but would make sense because there's no dtoverlay statement regarding uarts. I *do not* connect the power wire. The connecting machine is also a freebsd machine (amd64) I think connected in this way that this uart must be hardware and the disable-bt statement has something to do with it. [1] as fast as possible with 100% reliability, 24/7 [2] i'm sure you know, but bear in mind that not all silicon is equal,=20 so some might not get to 2GHz without reliability issues --=20 J. --c0mFzSTqqElW16HK Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEE8n3tWhxW11Ccvv9/s8o7QhFzNAUFAmBTnzwACgkQs8o7QhFz NAWU9A/7BZjBq9J4Tr4NZ/F+Znj3/ZZJPfQEtVHelij6pxMK6vl7BZmUYCaJc0fp WkHSh4OWn2jt68H10Z6pe2zvDrbNi4Lh4LCQlfxWhBOwzkXvSVlt0Hvsu+dcTJAI mOXDBoCYWEzWxcuXSmtLm6BNgznfscMuP6qPfpP+3bRirIs7nkMAQul5hu/3Ql61 lqrtCwgRcF64DJQZ+zZKyyFwkQsE/+WNo9Qa54C2TX+9glVGU8yoPf8TSjQIQsZ/ Fo5BVicZ/0pcsjAaSMkRN+idF2r1iQRHDswXpYaHW2DmWKVlReKn5ifeeZ+b/SmO loNJKmqfRa4Sl/ikX/gbvEPHJ4LizDj9gVgGerioxVCx2qv8jKlQZhhTP9GQgilz bNOO5tztE4Hx2YrEmjS6bBO1qFPiJrYaCFikoShT8G8SXgomre4+m2XeT+p3ggn+ v1QduvUUPRrBXKpaJvru+HsL2BprcvvTZVqNZlJlp5It+VNMuQjLM05vAkE/H9Ab 4tWGWmxKI8kUPlgYNlp9AJCqz7sgn7PMmUrNW1ALpB7vSNSiJbQptttArdbXpUQW vi+bbLWlPIM1tieg2WTsj387zyxZZP6s3YpFo6Q80MgMg0esnOkIsdN2HwiCTHPc rGYGMiER/lb5fi24eDw++INhoXDd0ViOMXBPoWdFKvPFZ5e9jdw= =u23L -----END PGP SIGNATURE----- --c0mFzSTqqElW16HK--
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