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Date:      Wed, 9 Mar 2016 20:34:08 +0200
From:      Jukka Ukkonen <jau789@gmail.com>
To:        Ian Lepore <ian@freebsd.org>, Hans Petter Selasky <hps@selasky.org>
Cc:        freebsd-arm <freebsd-arm@FreeBSD.org>
Subject:   Re: Odd hang during boot on RPI2 for 2 days now
Message-ID:  <56E06CA0.4030107@gmail.com>
In-Reply-To: <1457365690.13785.179.camel@freebsd.org>
References:  <56D99C2E.4020301@gmail.com> <56DD5DF8.9090700@gmail.com> <56DD6476.80603@selasky.org> <56DD9F60.7010509@gmail.com> <1457365690.13785.179.camel@freebsd.org>

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On 03/07/16 17:48, Ian Lepore wrote:
> On Mon, 2016-03-07 at 17:33 +0200, Jukka Ukkonen wrote:
>> On 03/07/16 13:22, Hans Petter Selasky wrote:
>>> On 03/07/16 11:54, Jukka Ukkonen wrote:
>>>>
>>>> Continuing where I previously left with this problem...
>>>> When I set boot_verbose=1 in loader.conf I got a little
>>>> more information before the poor RPI2 simply froze.
>>>> Now the last shown line was...
>>>>
>>>> random: harvesting attach, 8 bytes (4 bits) from ukbd0
>>>>
>>>> If I disconnect the USB keyboard and then reconnect it,
>>>> the kernel prints the normal detach and attach messages,
>>>> once again returns back to printing the "random: ..."
>>>> line shown above, and freezes again.
>>>>
>>>
>>> Then I think the init process is waiting for something. Would you
>>> manage
>>> to press CTRL+T in the console and see what is printed?
>>
>> The ctrl-T trick might work with a keyboard connected via
>> the serial line pins. With my USB keyboard and HDMI display
>> combo it doesn't do anything at all.
>> Surely the system must be waiting for something. Of that I
>> am quite certain. It does not panic and it keeps reacting to
>> the USB keyboard being disconnected and connected. Obviously
>> it is still otherwise fine, at least sort of, but also firmly
>> stuck waiting an event which either never happens or which
>> goes undetected for some reason.
> 
> Part of what's needed to diagnose this problem is dmesg output from a
> failed boot that is more than 1 or 2 lines snipped out of context.  It
> sounds to me like this has nothing to do with the usb keyboard except
> for the random coincidence that it is the last usb device to be
> enumerated.  It seems like the system is hung waiting for an interrupt,
> and there's no reason to think it's necessarily a usb interrupt that's
> missing.

Getting the dmesg output for the failed boot would require a serial
console cable connecting the RPI2 to another computer and script
running on the other computer to record the output. Lacking such
a cable this is a no-go of course.
A new fresh dmesg.boot file will be generated only after a normal
successful boot. And after a successful boot I would no longer need
the content of the file.

> Also, it seems unlikely that ^T will produce any output, because it
> sounds like init hasn't even started yet, and the low-level console
> used during boot doesn't respond to ^T/SIGINFO.

At least the system has already tried to start init. There is
a line ...

start_init: trying /sbin/init

shown some 30 lines before the freeze.

If anyone wishes to see a photo of what is shown on the display
when the system freezes, let me know. I will send a copy separately.
There are some 60-70 lines of text shown in the image.
I don't wish to spam the whole mailing list with a large image
file, though.

--jau




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