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Subject: Re: [REGRESSION 4.17] Spurious wakeup / reboot with power button
To:     Takashi Iwai <tiwai@suse.de>
Cc:     "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Erik Schmauss <erik.schmauss@intel.com>,
        Linux PM <linux-pm@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux ACPI <linux-acpi@vger.kernel.org>
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From:   =?UTF-8?Q?Thomas_H=c3=a4nig?= <haenig@cosifan.de>
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Date:   Fri, 6 Jul 2018 13:12:21 +0200
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Am 06.07.2018 um 08:55 schrieb Takashi Iwai:
> On Fri, 06 Jul 2018 07:18:36 +0200,
> Thomas H4nig wrote:
>>
>>
>>
>> Am 05.07.2018 um 18:56 schrieb Takashi Iwai:
>>> On Thu, 05 Jul 2018 18:02:11 +0200,
>>> Rafael J. Wysocki wrote:
>>>>
>>>> [The Lv's address is not valid any more, so drop it from the CC]
>>>>
>>>> On Thursday, July 5, 2018 5:10:20 PM CEST Rafael J. Wysocki wrote:
>>>>> On Thu, Jul 5, 2018 at 5:09 PM, Takashi Iwai <tiwai@suse.de> wrote:
>>>>>> On Thu, 05 Jul 2018 16:00:14 +0200,
>>>>>> Thomas H4nig wrote:
>>>>>>>
>>>>>>> Am 05.07.2018 um 14:12 schrieb Takashi Iwai:
>>>>>>>> On Thu, 05 Jul 2018 12:41:03 +0200,
>>>>>>>> Rafael J. Wysocki wrote:
>>>>>>>>>
>>>>>>>>> On Thursday, July 5, 2018 11:50:11 AM CEST Takashi Iwai wrote:
>>>>>>>>>> On Thu, 05 Jul 2018 11:34:59 +0200,
>>>>>>>>>> Rafael J. Wysocki wrote:
>>>>>>>>>>>
>>>>>>>>>>> Hi,
>>>>>>>>>>>
>>>>>>>>>>> On Thu, Jul 5, 2018 at 9:05 AM, Takashi Iwai <tiwai@suse.de> wrote:
>>>>>>>>>>>> Hi,
>>>>>>>>>>>>
>>>>>>>>>>>> we've got a regression report since 4.17 about the behavior of
>>>>>>>>>>>> power-off with the power button.  When a machine is powered off with
>>>>>>>>>>>> the power button on desktop, it reboots after a few seconds instead of
>>>>>>>>>>>> power down.
>>>>>>>>>>>>
>>>>>>>>>>>> The manual power down via "systemctl poweroff" works fine, so it's
>>>>>>>>>>>> possibly some spurious wakeup by the power button action, and some
>>>>>>>>>>>> ACPI-related change is suspected.
>>>>>>>>>>>> The regression still remains in 4.18-rc3.
>>>>>>>>>>>
>>>>>>>>>>> There are only a few ACPI commits directly related to power management
>>>>>>>>>>> between 4.16 and 4.17 and none of them looks particularly suspicious.
>>>>>>>>>>
>>>>>>>>>> OK, interesting.
>>>>>>>>>>
>>>>>>>>>>> It looks like the power button state may not be cleared sufficiently
>>>>>>>>>>> after it's been pressed which is now visible for some reason.
>>>>>>>>>>
>>>>>>>>>> Hmm, where can such a state remain?  Since it happens after the
>>>>>>>>>> machine turned off, some (ACPI) wakeup bits?
>>>>>>>>>
>>>>>>>>> Basically, yes.
>>>>>>>>>
>>>>>>>>> It looks like a GPE may remain active which then triggers wakeup after
>>>>>>>>> shutdown.
>>>>>>>>>
>>>>>>>>> On a hunch, I'm wondering if reverting commit
>>>>>>>>>
>>>>>>>>> 18996f2db918 ACPICA: Events: Stop unconditionally clearing ACPI IRQs during suspend/resume
>>>>>>>>>
>>>>>>>>> (may not revert clearly, though) makes any difference.
>>>>>>>>
>>>>>>>> OK, I'm building a 4.17.x test kernel with that revert, in OBS
>>>>>>>> home:tiwai:bsc1099930 repo.
>>>>>>>>
>>>>>>>> Thomas, could you try later the kernel in
>>>>>>>>   http://download.opensuse.org/repositories/home:/tiwai:/bsc1099930/standard/
>>>>>>>> ?  It'll take an hour or so until the build finishes.
>>>>>>>
>>>>>>> With your new built kernel
>>>>>>> 4.17.4-1.g6f23755-default
>>>>>>>
>>>>>>> the power button works again, so the revert solved the problem
>>>>>>
>>>>>> Thanks, that clarifies the cause.
>>>>>> Adding Erik and Lv to Cc.
>>>>>>
>>>>>> I guess it's the side-effect by removing
>>>>>>         acpi_ev_walk_gpe_list(acpi_hw_clear_gpe_block, NULL);
>>>>>> in acpi_hw_disable_all_gpes().
>>>>>>
>>>>>> This function is called from acpi_power_off_prepare(), and the machine
>>>>>> goes to power off without clearing the GPEs, hence it's woken up later
>>>>>> unexpectedly.
>>>>>
>>>>> That's correct.
>>>>>
>>>>> We need to fix up that commit.  I'll try to prepare something.
>>>>>
>>>>
>>>> Below is a patch to test that theory and maybe fix things if it is correct.
>>>>
>>>> What it does is to clear all GPEs after disabling them in
>>>> acpi_power_off_prepare() which should address the issue if our theory
>>>> about the underlying reason is correct.
>>>>
>>>> Please test.
>>>
>>> OK, building a new test kernel package in OBS home:tiwai:bsc1099930-2
>>> repo.  It'll appear at
>>>   http://download.opensuse.org/repositories/home:/tiwai:/bsc1099930-2/standard/
>>>
>>> Thomas, please give it a try later.
>>>
>>>
>>> thanks,
>>>
>>> Takashi
>>
>> I am sorry, but with your test kernel 4.17.4-1.g76c6238-default the
>> notebook again gets not properly powered off but restarts
> 
> Interesting.  The package version shows that the tested kernel must be
> the right one.  (Though, it'd be good to double-check -- it's often
> confusing if you have multiple same kernel versions on the system.)
> 
> If Rafael's patch doesn't work, we'd need to identify which change in
> the commit 18996f2db918 has the effect.
> 
> Thomas, could you try to build & modify the kernel in your side?
> Package build on OBS and test takes too long.
> 
> There are three places that remove the GPE-clearing in the patch.
> 
> One is in acpi_ev_enable_gpe():
> 
> --- a/drivers/acpi/acpica/evgpe.c
> +++ b/drivers/acpi/acpica/evgpe.c
> @@ -115,13 +115,6 @@ acpi_status acpi_ev_enable_gpe(struct acpi_gpe_event_info *gpe_event_info)
>  
>  	ACPI_FUNCTION_TRACE(ev_enable_gpe);
>  
> -	/* Clear the GPE (of stale events) */
> -
> -	status = acpi_hw_clear_gpe(gpe_event_info);
> -	if (ACPI_FAILURE(status)) {
> -		return_ACPI_STATUS(status);
> -	}
> -
>  	/* Enable the requested GPE */
>  
>  	status = acpi_hw_low_set_gpe(gpe_event_info, ACPI_GPE_ENABLE);
> 
> 
> ... the second one is in acpi_hw_disable_all_gpes():
> 
> --- a/drivers/acpi/acpica/hwgpe.c
> +++ b/drivers/acpi/acpica/hwgpe.c
> @@ -497,7 +497,6 @@ acpi_status acpi_hw_disable_all_gpes(void)
>  	ACPI_FUNCTION_TRACE(hw_disable_all_gpes);
>  
>  	status = acpi_ev_walk_gpe_list(acpi_hw_disable_gpe_block, NULL);
> -	status = acpi_ev_walk_gpe_list(acpi_hw_clear_gpe_block, NULL);
>  	return_ACPI_STATUS(status);
>  }
>  
> 
> ... and the last one is in acpi_hw_legacy_sleep():
> 
> --- a/drivers/acpi/acpica/hwsleep.c
> +++ b/drivers/acpi/acpica/hwsleep.c
> @@ -85,15 +85,8 @@ acpi_status acpi_hw_legacy_sleep(u8 sleep_state)
>  		return_ACPI_STATUS(status);
>  	}
>  
> -	/* Clear all fixed and general purpose status bits */
> -
> -	status = acpi_hw_clear_acpi_status();
> -	if (ACPI_FAILURE(status)) {
> -		return_ACPI_STATUS(status);
> -	}
> -
>  	/*
> 	 * 1) Disable/Clear all GPEs
> 
> 
> The rest are only comments changes.
> 
> Try to revert each hunk manually one-by-one and figure out which one
> actually causes the regression.  Maybe it'd be safer to test on the
> 4.17.x kernel, but you can check on 4.18-rc, too.
> 
> 
> thanks,
> 
> Takashi
> 

I am finally through and have results with patch(es) reverted for kernel
4.17.3-1-default:

1 - reboot
2 - reboot
3 - poweroff

being
#1 - evgpe.c
#2 - hwgpe.c
#3 - hwsleep.c

whereas the revert failed at #3 and I tried it manually, resulting in

whereas the revert failed at #3 and I tried it manually, resulting in

--- drivers/acpi/acpica/hwsleep.c       2018-07-06 12:56:07.881379862 +0200
+++ drivers/acpi/acpica/hwsleep.c.orig  2018-06-26 08:45:20.000000000 +0200
@@ -51,13 +51,6 @@ acpi_status acpi_hw_legacy_sleep(u8 slee
                return_ACPI_STATUS(status);
        }

-       /* Clear all fixed and general purpose status bits */
-
-       status = acpi_hw_clear_acpi_status();
-       if (ACPI_FAILURE(status)) {
-               return_ACPI_STATUS(status);
-       }
-
        /*
         * 1) Disable all GPEs
         * 2) Enable all wakeup GPEs