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

From: Kevin Hilman <khilman@linaro.org>
To: Santosh Shilimkar <santosh.shilimkar@ti.com>
Cc: Tony Lindgren <tony@atomide.com>, Roger Quadros <rogerq@ti.com>,
	"Menon, Nishanth" <nm@ti.com>,
	Grygorii Strashko <grygorii.strashko@ti.com>,
	Paul Walmsley <paul@pwsan.com>,
	Taras Kondratiuk <taras.kondratiuk@linaro.org>,
	"linux-omap@vger.kernel.org" <linux-omap@vger.kernel.org>,
	Linux ARM Kernel Mailing List
	<linux-arm-kernel@lists.infradead.org>,
	"Kristo, Tero" <t-kristo@ti.com>,
	Paul Burton <paul.burton@imgtec.com>,
	Daniel Lezcano <daniel.lezcano@linaro.org>,
	"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Subject: Re: omap4-panda-es boot issues with v3.15-rc4
Date: Mon, 12 May 2014 16:56:27 -0700	[thread overview]
Message-ID: <7hiopah7pw.fsf@paris.lan> (raw)
In-Reply-To: <53713FCF.3000006@ti.com> (Santosh Shilimkar's message of "Mon, 12 May 2014 17:40:31 -0400")

Santosh Shilimkar <santosh.shilimkar@ti.com> writes:

> On Sunday 11 May 2014 11:55 AM, Tony Lindgren wrote:
>> * Kevin Hilman <khilman@linaro.org> [140509 16:46]:
>>> Roger Quadros <rogerq@ti.com> writes:
>>>
>>>> Kevin,
>>>>
>>>> On 05/09/2014 01:15 AM, Kevin Hilman wrote:
>>>>> Tony Lindgren <tony@atomide.com> writes:
>>>>>
>>>>> [...]
>>>>>
>>>>>> ..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