Date: Sat, 28 Sep 2013 01:18:07 +0200 From: Bernd Walter <ticso@cicely7.cicely.de> To: Tim Kientzle <kientzle@freebsd.org> Cc: freebsd-arm@freebsd.org, ticso@cicely.de Subject: Re: FreeBSD on Cubieboard 2, UDOO and Galaxy Note 10.1 (Exynos). Message-ID: <20130927231807.GG82284@cicely7.cicely.de> In-Reply-To: <8F8B0558-4B7A-4BC6-BF93-A89E5533C567@freebsd.org> References: <C085FFE7-994E-4371-B754-4846008E2048@yahoo.de> <CAGtf9xPDSy38_zDZssnfA8qqJjwUCQ_3yfoAm7DKYEzN3tdwUQ@mail.gmail.com> <1378866956.1111.608.camel@revolution.hippie.lan> <F7549C24-7B19-402A-914D-B70C9E483EA4@yahoo.de> <1379101800.1111.642.camel@revolution.hippie.lan> <20130926223120.GM65622@cicely7.cicely.de> <8F8B0558-4B7A-4BC6-BF93-A89E5533C567@freebsd.org>
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On Thu, Sep 26, 2013 at 07:43:39PM -0700, Tim Kientzle wrote: > > On Sep 26, 2013, at 3:31 PM, Bernd Walter <ticso@cicely7.cicely.de> wrote: > > > I also noted that the Beaglebone Black seems to run at 550MHz only. > > I've found out from NetBSD mailinglist, that the PLL must be > > reprogrammed for higer frequency and the core voltage needs adjustment > > too. > > Of those 3 boards the BBB was the only board mention CPU frequency at all. > > I've not looked into the code required, but I know some of the issues: > > * For the older "white" Beaglebone, at least, the CPU frequency > needs to be set properly depending on the power supply. So > "someone" needs to read the PMIC and determine whether > power is coming from the 5V input or from USB. In the latter > case, I believe the lower frequency may be appropriate. > > * For BB White, I believe the "someone" was U-Boot; the FreeBSD > kernel just assumed the CPU was already properly initialized. > I haven't looked to see if the U-Boot we're using now does power > config for BBB. > > * We should add a PMIC driver and do this setting in our kernel. This matches with what I got from reading some mails on a NetBSD list: http://mail-index.netbsd.org/port-arm/2013/08/01/msg001932.html I didn't find any definitive answer about barrel plug vs. USB supply. It seems that via USB the performance is to be reduced. However using a lab supply I measured via barrel plug supply 270mA with 550MHz FreBSD and 320mA with preinstalled Linux at unknown frequency. Maybe precaution for higher load, or USB devices sucking power. -- B.Walter <bernd@bwct.de> http://www.bwct.de Modbus/TCP Ethernet I/O Baugruppen, ARM basierte FreeBSD Rechner uvm.
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