[PATCH] ARM: exynos_defconfig: disable CONFIG_EXYNOS5420_MCPM; not stable

[Krzysztof Kozlowski]

On pon, 2014-11-24 at 19:20 -0800, Kevin Hilman wrote:
> On Mon, Nov 24, 2014 at 5:50 PM, Kukjin Kim <kgene at kernel.org> wrote:
> > Olof Johansson wrote:
> >>
> >> On Mon, Nov 24, 2014 at 5:37 PM, Olof Johansson <olof at lixom.net> wrote:
> >> > On Mon, Nov 24, 2014 at 5:35 PM, Kevin Hilman <khilman at kernel.org> wrote:
> >> >> On Mon, Nov 24, 2014 at 4:25 PM, Olof Johansson <olof at lixom.net> wrote:
> >> >>> On Mon, Nov 24, 2014 at 11:51 AM, Kevin Hilman <khilman at kernel.org> wrote:
> >> >>>>
> >> >>>> Is anyone at Samsung actually looking into these MCPM issues?
> >> >>>
> >> >>> Hi Kevin,
> >> >>>
> >> >>> What hardware are you having problems with? 5420 or 5422/5800?
> >> >>
> >> >> Yes.  :)
> >> >>
> >> >> exynos5420-arndale-octa:
> >> >> http://storage.armcloud.us/kernel-ci/mainline/v3.18-rc6/arm-exynos_defconfig/boot-exynos5420-
> >> arndale-octa.html
> >> >> exynos5422-odroid-xu3:
> >> >> http://storage.armcloud.us/kernel-ci/mainline/v3.18-rc6/arm-exynos_defconfig/boot-exynos5422-
> >> odroid-xu3.html
> >> >>
> >> >> My boot tests seem to pass fine because I have such a minimal
> >> >> userspace, but Tyler Baker reported that with a "real" userspace, he
> >> >> can't boot to a shell:
> >> >>
> >> >>   http://lists.infradead.org/pipermail/linux-arm-kernel/2014-September/286203.html
> >> >
> > Hmm...his report was in Sep...I think it should be fine with current -next?
> 
> No, it is still broken in linux-next (as I stated above.)
> 
> Moreover, earlier in this thread you mentioned you were merging some
> MCPM patches that should address this, but did not respond when I
> asked which patches you thing should address this issue
> 
> > To be honest, since I don't have the exynos5420 arndale, chromebook...but smdk
> > which has different bootloader, I couldn't test it...I'll try to make a test
> > farm like you guys...
> 
> Do you have some colleagues with any other 542x hardware?  I had
> assumed that linux-next was being better tested on the publicaly
> available, and widely available boards like odroid-xu3 and
> Chromebook2, but I've come to realize the hard way that that is not
> the case.  You mention your board has a different bootloader.  Do you
> suspect there's a bootloader issue on these other platforms?  If so,
> could you elaborate on possible fixes?  I'm more than willing to test
> any proposed fixes, but I'm not familiar enough yet with these SoCs to
> figure out the underlying issues alone.
> 
> Until you have a working board farm, you could start having a closer
> look at the boot logs we're already producing.  Admittedly linux-next
> broken in many ways besides this one for exynos currently, but it has
> been having these imprecise aborts well before the other recent
> issues.
> 
> Also, It's very possible that this issue is not even MCPM related at
> all, and MCPM is just uncovering a previously hidden bug.  It would be
> very helpful if people more familiar with this hardware and SoC would
> investigate bug reports like these.

Interesting thing can be found in exynos5420.dtsi:
mdma1: mdma at 11C10000 {
	...
	/*
	 * MDMA1 can support both secure and non-secure
	 * AXI transactions. When this is enabled in the kernel
	 * for boards that run in secure mode, we are getting
	 * imprecise external aborts causing the kernel to oops.
	 */
	status = "disabled";
};

I am booting Arndale Octa on some other config and exynos. However with
or without MCPM the imprecise aborts are still present (but not fatal,
shell comes up).

My board boots also under secure firmware (I am using Linaro's ubuntu
image). Maybe that is the cause?

Best regards,
Krzysztof