Re: Peach Pi/Pit boot failures in linux-next (was Re: [RFC PATCH 1/1] drm/exynos: Move platform drivers registration to module init)

[Kevin Hilman <khilman@kernel.org>]

Javier Martinez Canillas <javier.martinez@collabora.co.uk> writes:

> [adding Kukjin as cc and dropping dri-devel]
>
> Hello Kevin,
>
> On 11/20/2014 07:22 PM, Kevin Hilman wrote:
>>> My kernel command line is almost the same with the difference that
>>> I'm using clk_ignore_unused and I just checked that not passing
>>> that parameter, makes linux-next to hang showing the same output
>>> log that Kevin reported.
>> 
>> Ah!  Good find.  I confirm that adding clk_ignore_unused is getting
>> me booting again, but of course that is just masking a problem, so I
>> hope someone can shed light on which clock isn't being correctly
>> managed.
>> 
>
> True, I'm renaming the thread subject to track these issues separately
> of the original Exynos DRM bug since these are unrelated.
>
> So, I see two different boot failures on the Peach Pi[t] Chromebooks:
>
> 1) next20141121 boot fails due snd-soc-snow
>
> Disabling CONFIG_SND_SOC_SNOW makes the boot to got a little further
> but still fails with the second issue:
>
> 2) next20141121 boot hangs if unused clocks are disabled.
>
> I tried to root cause these two issues but didn't see anything evident
> so I'll find a last known good commit and bisect. If anyone has an
> idea of the possible causes for these issues that would be appreciated.

FWIW, in addition to the failures on 5800/peach-pi, I'm also seeing boot
failures in next-20141121 on the exynos5420-arndale-octa[1].  Adding
clk_ignore_unused gets things booting there as well.

What's interesting is that my exynos5422-odroid-xu3 is booting fine as
well as the exynos5420-arndale and the exynos5410-odroid-xu (shown as
exynos5410-smdk5410)

Whatever the issue, it definietly seems like a problem that was came
through a driver/subsystem tree because that these boards are all
booting fine with Kukjin's for-next, arm-soc/for-next and
mainline/v3.18-rc5 (all with just plain exynos_defconfig, and without
clk_ignore_unused.)  For example, just looking at peach-pi across all
these trees[2], you can see that it's only failing in linux-next.

Kevin

[1] http://status.armcloud.us/boot/?next-2014112?&exynos
[2] http://status.armcloud.us/boot/?exynos5800-peach-pi

NOTE: the exynos5422-odroid-xu3 is shown as exynos5420-smdk5420 since
      that's the DTS being used, and exynos5410-odroid-xu is shown as
      exynos5410-smdk5410, again due to the DTS being used.