omap4-panda-es boot issues with v3.15-rc4

Santosh Shilimkar [off-list ref] writes:

On Sunday 11 May 2014 11:55 AM, Tony Lindgren wrote:

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* Kevin Hilman [off-list ref] [140509 16:46]:

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Roger Quadros [off-list ref] writes:

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Kevin,

On 05/09/2014 01:15 AM, Kevin Hilman wrote:

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Tony Lindgren [off-list ref] writes:

[...]

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..but I think I found the cause for recent hangs on panda, just a wild
guess based on looking at the recent cpuidle patches after v3.14.

Looks like reverting 0b89e9aa2856 (cpuidle: delay enabling interrupts
until all coupled CPUs leave idle) makes booting work reliably again
on panda.

Can you guys confirm, so far no issues here after few boot tests,
but it might be too early to tell.

Reverting that makes things a bit more stable, but it still eventually
fails in the same way.  For me it took 8 boots for it to eventually
fail.

However, if I build with CONFIG_CPU_IDLE=n, it becomes much more stable
(20+ boots in a row and still going.)

Can you please test with CPU_IDLE enabled but C3 disabled as in below patch?
It worked for me 10/10 boots.

Yup, it worked for me too for 10/10 boots in a row.

But what has caused this regression, does it work reliably with let's
say v3.13 or v3.12?

IIRC things were stable till some CPUIDLE code consolidation happened.
I don't recall exactly but some one did discuss about it a while back.

Can you re-run your test-cases with patch at end of the email. This
is just a hunch so don't blame me if I waste your time testing the
patch.

With your patch applied on top of next-20140512, my 4460 Panda-ES has
booted 25 times in a row, and still going.

Kevin