Date: Tue, 30 Oct 2012 08:22:40 -0600 From: Ian Lepore <freebsd@damnhippie.dyndns.org> To: Alie Tan <alie@affle.com> Cc: "freebsd-arm@freebsd.org" <freebsd-arm@freebsd.org> Subject: Re: BeagleBone questions (was Re: Towards an ARM system-building script) Message-ID: <1351606960.1120.21.camel@revolution.hippie.lan> In-Reply-To: <CANuCnH_Dc1XWUmhHmmpOHTGy%2Bjh5AjuVrOzVKE-QA=3zjfTDRA@mail.gmail.com> References: <CANuCnH-Y_Bixer7s5EEU4sJVjRC7s3QQbpJeevdXTpxS2K0OqA@mail.gmail.com> <2E208EEB-B2CF-4AC6-B420-03FB4CF08041@freebsd.org> <1351522908.1123.356.camel@revolution.hippie.lan> <CANuCnH9KcRvp2yKeKg6Tp%2Ba2tZLc7RdhRzQiQ9C2VDcHZwAEEg@mail.gmail.com> <CAJ-VmokQmJbr0P4xp9PHHXC5_q0Fte18atvQu28QX%2B2oZiYmrw@mail.gmail.com> <1351550400.1123.364.camel@revolution.hippie.lan> <CANuCnH_Dc1XWUmhHmmpOHTGy%2Bjh5AjuVrOzVKE-QA=3zjfTDRA@mail.gmail.com>
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On Tue, 2012-10-30 at 18:42 +0800, Alie Tan wrote: > On Tue, Oct 30, 2012 at 6:40 AM, Ian Lepore > <freebsd@damnhippie.dyndns.org>wrote: > > > On Mon, 2012-10-29 at 09:14 -0700, Adrian Chadd wrote: > > > On 29 October 2012 08:08, Alie Tan <alie@affle.com> wrote: > > > > I have tried angstrom, ArchLinux and FreBSD. Only FreeBSD makes the > > > > chip/board quite hot. > > > > > > > > Anyone have same experiece? > > > > > > Are we not halting the CPU during idle ticks on ARM? > > > > > > Does Linux have some extra power management code for ARM that we don't? > > > > I'm not sure all arm SoCs we support have the ability to do this well > > (or at all). I know for sure the atmel chips can do it, and we don't > > use that abillity. We're pretty poor on power management in general in > > the atmel world. I mean poor, like we turn on all on-chip devices early > > in kernel init and leave them that way, even the ones we don't have > > drivers for. A comment in the code labels that a "temporary hack" but > > it's been that way for 5 years. > > > > More directly on the OP's point, I wonder if the combo of the system not > > fully booting and too much heat imply that something has gone into a > > tight loop somewhere. > > > Is there any way to debug/detect this issue? > I cant see any heavy processes from 'top' > Well if the system is running well enough to use top, and it isn't showing any process or kernel thread using a ton of cpu, then I think that probably invalidates my theory. One of my arm eval boards has an LCD interface that I don't use, and a note with the system mentioned that there's a part on the board that will heat up if you don't connect a display; they recommend unsoldering it. The part is some sort of choke or coil (it's silkscreened as "L11"). On my board it gets warm, not really hot, so I haven't bothered to remove it. -- Ian
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