Re: boot hang on commit "PM / ACPI: Fix suspend/resume regression caused by cpuidle cleanup."

[Deepthi Dharwar <deepthi@xxxxxxxxxxxxxxxxxx>]

Hi,

This is interesting .. suspend fix breaking boot on kvm.

We complied and booted fine with mainline kernels including 3.5-rc2 with
this fix  on servers and laptops.
So wondering how different is  booting on machines Vs
from kvm ?

Also, are you seeing smooth boot on kvm by reverting only this patch ?

Cheers
Deepthi

On 06/22/2012 01:05 PM, wfg@xxxxxxxxxxxxxxx wrote:

> Hi Deepthi,
> 
> It seems that commit de08622 triggers a boot hang in my kvm boot test.
> 
> kvm -cpu kvm64 -enable-kvm \
>                 -kernel ./gpxelinux.lkrn \
>                 -initrd ./kvm.gpxe \
>                 -m 384M \
>                 -net nic,vlan=0,macaddr=00:00:00:00:00:00,model=e1000  \
>                 -net user,vlan=0,hostfwd=tcp::$port-:22 \
>                 -boot order=nc \
>                 -no-reboot \
>                 -watchdog i6300esb \
>                 $(qemu_drives) \
>                 -pidfile $pidfile \
>                 -serial file:$dmesg 
> 
> tree:   git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next
> head:   de08622731417ba429fc470ab8f2d7c260cb5c72
> commit: de08622731417ba429fc470ab8f2d7c260cb5c72 [9/9] PM / ACPI: Fix suspend/resume regression caused by cpuidle cleanup.
> config: x86_64-allyesdebian (attached as .config)
> 
> x86_64-allyesdebian         bbbbbbbbbB
> --
> 8:	b 0eb8c06  2012-06-19 22:23:37 +0200 PM / Sleep: Separate printing suspend times from initcall_debug
> 9:	B de08622  boot hang after [   81.370898] usbcore: registered new interface driver dw2102
> 
> legend: [b] boot fine  [B] boot error
> 
> commit de08622731417ba429fc470ab8f2d7c260cb5c72
> Author: Deepthi Dharwar <deepthi@xxxxxxxxxxxxxxxxxx>
> Date:   Wed Jun 13 16:28:17 2012 +0530
> 
>     PM / ACPI: 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.
>     
>     Signed-off-by: Deepthi Dharwar <deepthi@xxxxxxxxxxxxxxxxxx>
>     Reported-and-Tested-by: Dav Hansen <dave@xxxxxxxxxxxxxxxxxx>
>     Tested-by: Preeti Murthy <preeti@xxxxxxxxxxxxxxxxxx>
>     Reviewed-by: Srivatsa S Bhat <srivatsa.bhat@xxxxxxxxxxxxxxxxxx>
>     Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>
> 
> 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,


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