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Date: Fri, 15 Jun 2012 17:57:50 +0530
From: Deepthi Dharwar <deepthi@...ux.vnet.ibm.com>
To: "Rafael J. Wysocki" <rjw@...k.pl>
CC: Dave Hansen <dave@...ux.vnet.ibm.com>,
Linux PM mailing list <linux-pm@...r.kernel.org>,
linux-pm@...ts.linux-foundation.org, linux-acpi@...r.kernel.org,
Len Brown <len.brown@...el.com>, Jean Pihet <j-pihet@...com>,
Arjan van de Ven <arjan@...ux.intel.com>,
Kevin Hilman <khilman@...com>, Arnd Bergmann <arnd@...db.de>,
Ferenc Wagner <wferi@...f.hu>,
"Tomas M." <tmezzadra@...il.com>,
"Srivatsa S. Bhat" <srivatsa.bhat@...ux.vnet.ibm.com>,
preeti@...ux.vnet.ibm.com,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
stable@...r.kernel.org
Subject: Re: [PATCH] ACPI, cpuidle: Fix suspend/resume regression caused by
cpuidle cleanup.
Apologies for the confusion.
Please add the Cc: stable tag for this patch as this regression affects
older kernels too.
Link to the patch :
http://permalink.gmane.org/gmane.linux.power-management.general/27614
Thanks !
Deepthi
On 06/15/2012 05:46 PM, Deepthi Dharwar wrote:
> Please include this in -stable tree, as this is a regression fix which
> affects older kernels ( 3.1 onwards )
> Link to the patch :
> http://permalink.gmane.org/gmane.linux.power-management.general/27614
>
> Thanks !
> Deepthi
>
> On 06/14/2012 01:31 AM, Rafael J. Wysocki wrote:
>
>> On Wednesday, June 13, 2012, Deepthi Dharwar wrote:
>>>
>>> From: Deepthi Dharwar <deepthi@...ux.vnet.ibm.com>
>>>
>>> Fix suspend/resume regression caused by cpuidle cleanup.
>>>
>>> Commit e978aa7d7d57d04eb5f88a7507c4fb98577def77 ( cpuidle: Move
>>> dev->last_residency update to driver enter routine; remove dev->last_state)
>>> was breaking suspend on laptops, as reported in the below link
>>> - https://lkml.org/lkml/2011/11/11/164
>>>
>>> This was fixed in commit 3439a8da16bcad6b0982ece938c9f8299bb53584
>>> (ACPI / cpuidle: Remove acpi_idle_suspend (to fix suspend regression)
>>> by removing acpi_idle_suspend flag.
>>> - https://lkml.org/lkml/2011/11/14/74
>>>
>>> But this fix did not work on all systems
>>> as Suspend/resume regression was reported on Lenovo S10-3
>>> recently by Dave.
>>> - https://lkml.org/lkml/2012/5/27/115
>>> It looked like with commit e978aa7d broke suspend and
>>> with commit 3439a8da resume was not working with acpi_idle driver.
>>>
>>> This patch fixes the regression that caused this issue
>>> in the first place. acpi_idle_suspend flag is essential on
>>> some x86 systems to prevent the cpus from going to deeper C-states
>>> when suspend is triggered ( commit b04e7bdb984 )
>>> So reverting the commit 3439a8da is essential.
>>>
>>> By default, irqs are disabled in cpu_idle arch specific call
>>> and re-enabled in idle state return path . As the acpi_idle_suspend
>>> flag was being set during suspend, which prevented the cpus
>>> going to deeper idle states, it is essential to
>>> enabling the irqs in its return path too.
>>>
>>> To address the suspend issue,
>>> we were not re-enabling the interrupts while returning from
>>> acpi_idle_enter_bm() routine if acpi_idle_suspend flag is set.
>>> and this was causing suspend failure.
>>>
>>> In addition to the above fix, a sanity check has also been added
>>> in x86 arch specific cpu_idle call to ensure that the idle call
>>> always returns with IRQs enabled.
>>>
>>> This patch applies on 3.5-rc2
>>> ---
>>>
>>> Reported-and-Tested-by: Dav Hansen <dave@...ux.vnet.ibm.com>
>>> Tested-by: Preeti Murthy <preeti@...ux.vnet.ibm.com>
>>> Signed-off-by: Deepthi Dharwar <deepthi@...ux.vnet.ibm.com>
>>> Reviewed-by: Srivatsa S Bhat <srivatsa.bhat@...ux.vnet.ibm.com>
>>
>> Acked-by: Rafael J. Wysocki <rjw@...k.pl>
>>
>>> ---
>>> arch/x86/kernel/process.c | 6 ++++++
>>> drivers/acpi/processor_idle.c | 28 ++++++++++++++++++++++++++++
>>> 2 files changed, 34 insertions(+), 0 deletions(-)
>>>
>>> diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
>>> index 735279e..8ab76ad 100644
>>> --- a/arch/x86/kernel/process.c
>>> +++ b/arch/x86/kernel/process.c
>>> @@ -460,6 +460,12 @@ void cpu_idle(void)
>>> pm_idle();
>>>
>>> rcu_idle_exit();
>>> +
>>> + /*
>>> + * Sanity check to ensure that idle call returns
>>> + * with IRQs enabled
>>> + */
>>> + WARN_ON(irqs_disabled());
>>> start_critical_timings();
>>>
>>> /* In many cases the interrupt that ended idle
>>> diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
>>> index f3decb3..c2ffd84 100644
>>> --- a/drivers/acpi/processor_idle.c
>>> +++ b/drivers/acpi/processor_idle.c
>>> @@ -224,6 +224,7 @@ static void lapic_timer_state_broadcast(struct acpi_processor *pr,
>>> /*
>>> * Suspend / resume control
>>> */
>>> +static int acpi_idle_suspend;
>>> static u32 saved_bm_rld;
>>>
>>> static void acpi_idle_bm_rld_save(void)
>>> @@ -242,13 +243,21 @@ static void acpi_idle_bm_rld_restore(void)
>>>
>>> int acpi_processor_suspend(struct acpi_device * device, pm_message_t state)
>>> {
>>> + if (acpi_idle_suspend == 1)
>>> + return 0;
>>> +
>>> acpi_idle_bm_rld_save();
>>> + acpi_idle_suspend = 1;
>>> return 0;
>>> }
>>>
>>> int acpi_processor_resume(struct acpi_device * device)
>>> {
>>> + if (acpi_idle_suspend == 0)
>>> + return 0;
>>> +
>>> acpi_idle_bm_rld_restore();
>>> + acpi_idle_suspend = 0;
>>> return 0;
>>> }
>>>
>>> @@ -754,6 +763,12 @@ static int acpi_idle_enter_c1(struct cpuidle_device *dev,
>>>
>>> local_irq_disable();
>>>
>>> + if (acpi_idle_suspend) {
>>> + local_irq_enable();
>>> + cpu_relax();
>>> + return -EINVAL;
>>> + }
>>> +
>>> lapic_timer_state_broadcast(pr, cx, 1);
>>> kt1 = ktime_get_real();
>>> acpi_idle_do_entry(cx);
>>> @@ -823,6 +838,12 @@ static int acpi_idle_enter_simple(struct cpuidle_device *dev,
>>>
>>> local_irq_disable();
>>>
>>> + if (acpi_idle_suspend) {
>>> + local_irq_enable();
>>> + cpu_relax();
>>> + return -EINVAL;
>>> + }
>>> +
>>> if (cx->entry_method != ACPI_CSTATE_FFH) {
>>> current_thread_info()->status &= ~TS_POLLING;
>>> /*
>>> @@ -901,6 +922,13 @@ static int acpi_idle_enter_bm(struct cpuidle_device *dev,
>>> if (unlikely(!pr))
>>> return -EINVAL;
>>>
>>> + if (acpi_idle_suspend) {
>>> + if (irqs_disabled())
>>> + local_irq_enable();
>>> + cpu_relax();
>>> + return -EINVAL;
>>> + }
>>> +
>>> if (!cx->bm_sts_skip && acpi_idle_bm_check()) {
>>> if (drv->safe_state_index >= 0) {
>>> return drv->states[drv->safe_state_index].enter(dev,
>>>
>>> Regards,
>>> Deepthi
>>>
>>>
>>>
>>
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