MTK mt8173-evb: mainline unstable, and big-endian boot failures

Eddie Huang
2016-01-28T06:56:20Z

On Thu, 2016-01-28 at 13:41 +0800, Koan-Sin Tan wrote:
> Hi Kevin,
>
> On Thu, Jan 28, 2016 at 9:16 AM, Kevin Hilman <khilman@baylibre.com>
> wrote:
> Kevin Hilman <khilman@baylibre.com> writes:
>
> [...]
>
> > It seems to be pretty stable up through v4.4 but
> > unreliable/unpredictable in v4.5-rc1 and lots of places in
> between.
> > It's hard to bisect because it doesn't reliably fail, but
> when it does
> > fail to finish booting, it's typically after it reaches a
> shell, and
> > trying to run various simple shell commands fails to
> complete, like
> > this example from next-20160125[2].
> >
> > To me this suggests possibly an issue with the idle driver
> where
> > characters might be getting lost on the serial console,
> which causes
> > the automated boot scripts to fail because the shell is
> still waiting
> > for the command to be finished.
>
> FWIW, I think I confirmed my suspicion that it's an idle
> driver issue
> because adding 'nohlt' on the cmdline, which forces
> cpuidle_poll mode
> (essentially disabling cpuidle) makes mainline boot quite
> reliably on my
> mt8173-evb board now.
>
>
> Thanks for the information. I'll try to reproduce it. The problem
> is that I have been using 4.5-rc1 based kernel for several days, but
> didn't run into such problem. Can tell me which version of firmware
> you are using?

Hi Kevin,

I use firmware [0] to run kernel v4.5-rc1 on my MT8173-evb, both branch
v20150716 (psci-0.2 atf) and v20150902 (psci-1.0 atf) can't reproduce
this problem.

[0]: https://github.com/ibanezchen/evb-utils

Eddie

>
> And, YES, I can reproduce the CONFIG_CPU_BIG_ENDIAN=y problem. The
> 'nohlt' command line option didn't stop the problem. We'll investigate
> it.
>
>
> --
> // freedom