From: daniel.lezcano@linaro•org (Daniel Lezcano)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH] ARM: OMAP4: Fix the boot regression with CPU_IDLE enabled
Date: Wed, 14 May 2014 22:02:01 +0200 [thread overview]
Message-ID: <5373CBB9.40506@linaro.org> (raw)
In-Reply-To: <5373C8E8.6040208@ti.com>
On 05/14/2014 09:50 PM, Santosh Shilimkar wrote:
> On Wednesday 14 May 2014 03:44 PM, Daniel Lezcano wrote:
>> On 05/13/2014 04:39 PM, Santosh Shilimkar wrote:
>>> On OMAP4 panda board, there have been several bug reports about boot
>>> hang and lock-ups with CPU_IDLE enabled. The root cause of the issue
>>> is missing interrupts while in idle state. Commit cb7094e8 {cpuidle / omap4 :
>>> use CPUIDLE_FLAG_TIMER_STOP flag} moved the broadcast notifiers to common
>>> code for right reasons but on OMAP4 which suffers from a nasty ROM code
>>> bug with GIC, commit ff999b8a {ARM: OMAP4460: Workaround for ROM bug ..},
>>> we loose interrupts which leads to issues like lock-up, hangs etc.
>>>
>>> Patch reverts commit cb7094 {cpuidle / omap4 : use CPUIDLE_FLAG_TIMER_STOP
>>> flag} to avoid the issue. With this change, OMAP4 panda boards, the mentioned
>>> issues are getting fixed. We no longer loose interrupts which was the cause
>>> of the regression.
>>>
>>> Cc: Roger Quadros <rogerq@ti•com>
>>> Cc: Kevin Hilman <khilman@linaro•org>
>>> Cc: Tony Lindgren <tony@atomide•com>
>>> Cc: Daniel Lezcano <daniel.lezcano@linaro•org>
>>> Reported-tested-by: Roger Quadros <rogerq@ti•com>
>>> Reported-tested-by: Kevin Hilman <khilman@linaro•org>
>>> Tested-by: Tony Lindgren <tony@atomide•com>
>>> Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti•com>
>>> ---
[ ... ]
>>>
>>> + clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu_id);
>>> +
>>> /*
>>> * Call idle CPU PM enter notifier chain so that
>>> * VFP and per CPU interrupt context is saved.
>>> @@ -165,6 +169,8 @@ static int omap_enter_idle_coupled(struct cpuidle_device *dev,
>>> if (dev->cpu == 0 && mpuss_can_lose_context)
>>> cpu_cluster_pm_exit();
>>>
>>> + clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &cpu_id);
[ ... ]
>>
>> Shouldn't the broadcast timer to be setup with CLOCK_EVT_NOTIFY_BROADCAST_ON also ?
>>
> Which is already taken care by __cpuidle_register_driver(). Note that setup code
> is still used from generic code...
Nope, if the flag CPUIDLE_FLAG_TIMER_STOP is not set, the cpuidle
framework won't setup the timer.
static void __cpuidle_driver_init(struct cpuidle_driver *drv)
{
...
for (i = drv->state_count - 1; i >= 0 ; i--) {
if (drv->states[i].flags & CPUIDLE_FLAG_TIMER_STOP) {
drv->bctimer = 1;
break;
}
}
...
}
static int __cpuidle_register_driver(struct cpuidle_driver *drv)
{
...
if (drv->bctimer)
on_each_cpu_mask(drv->cpumask,
cpuidle_setup_broadcast_timer,
(void *)CLOCK_EVT_NOTIFY_BROADCAST_ON, 1);
...
}
So the broadcast timer does not operate with this revert. Moreover, I am
not sure reverting this patch is the right solution.
--
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next prev parent reply other threads:[~2014-05-14 20:02 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-13 14:39 [PATCH] ARM: OMAP4: Fix the boot regression with CPU_IDLE enabled Santosh Shilimkar
2014-05-14 15:22 ` Tony Lindgren
2014-05-14 19:44 ` Daniel Lezcano
2014-05-14 19:50 ` Santosh Shilimkar
2014-05-14 20:02 ` Daniel Lezcano [this message]
2014-05-14 20:56 ` Tony Lindgren
2014-05-14 23:31 ` Tony Lindgren
2014-05-16 0:13 ` Tony Lindgren
2014-05-16 0:40 ` Tony Lindgren
2014-05-14 21:18 ` Santosh Shilimkar
2014-05-15 17:03 ` Santosh Shilimkar
2014-05-15 17:50 ` Daniel Lezcano
2014-05-15 17:54 ` Santosh Shilimkar
2014-05-15 18:29 ` Santosh Shilimkar
2014-05-16 0:33 ` Alex Shi
2014-05-16 13:43 ` Santosh Shilimkar
2014-05-16 21:29 ` Tony Lindgren
2014-05-19 16:45 ` Daniel Lezcano
2014-05-19 17:23 ` Tony Lindgren
2014-05-19 17:34 ` Santosh Shilimkar
2014-05-19 17:51 ` Tony Lindgren
2014-05-19 18:06 ` Daniel Lezcano
2014-05-19 19:36 ` Tony Lindgren
2014-05-19 19:45 ` Daniel Lezcano
2014-05-19 21:18 ` Tobias Jakobi
2014-05-19 22:42 ` Tony Lindgren
2014-05-23 14:44 ` Tony Lindgren
2014-05-23 18:32 ` Tony Lindgren
[not found] ` <CAKnoXLxj42veWCbRjX98iT3FNAb92J4yR+UAL716JFSOb=pcrQ@mail.gmail.com>
2014-05-27 20:34 ` Tony Lindgren
2014-05-27 21:03 ` Santosh Shilimkar
2014-05-27 21:06 ` Daniel Lezcano
2014-05-19 20:00 ` Santosh Shilimkar
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