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Subject: Re: [PATCH] ACPI / LPSS: Don't skip late system PM ops for hibernate
 on BYT/CHT
To:     "Robert R. Howell" <RHowell@uwyo.edu>,
        "Rafael J. Wysocki" <rafael@kernel.org>
Cc:     Kai-Heng Feng <kai.heng.feng@canonical.com>,
        "rjw@rjwysocki.net" <rjw@rjwysocki.net>,
        "lenb@kernel.org" <lenb@kernel.org>,
        "linux-acpi@vger.kernel.org" <linux-acpi@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
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From:   Hans de Goede <hdegoede@redhat.com>
Message-ID: <8e5b82ce-4120-4d81-fd8c-26a16cfe3381@redhat.com>
Date:   Mon, 13 May 2019 10:41:33 +0200
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Hi Robert,

On 09-05-19 20:09, Robert R. Howell wrote:
> Hi Hans
> 
> On 5/9/19 2:50 AM, Hans de Goede wrote:
> 
>>
>> Hi,
>>
>> On 09-05-19 06:24, Robert R. Howell wrote:
>>> On 4/30/19 8:39 AM, Hans de Goede wrote:
>>>>
> 
>>>>
>>>> I've just tried to reproduce the "Error i2c_dw_xfer call while suspended" error
>>>> on suspend/resume on my own T100TA and I could not reproduce this.
>>>>
>>>> Can you try without the BT keyboard paired and waking up from suspend using the
>>>> tablet part's power-button ?
>>>>
>>>> Also do you still have the scripts to rmmod some modules before suspend ?
>>>>
>>>
>>> The T100TA keyboard is actually a hardwired connection rather than Bluetooth but I
>>> did physically disconnect the keyboard, and also unpaired all the actual Bluetooth
>>> devices (such as the mouse) and then powered down the T100TA bluetooth adapter.
>>> When I suspend, then resume using the tablet power button, I still get the
>>> i2c_dw_xfererror error during the resume.  But whatever causes this error isn't fatal,
>>> in the sense that after resume the sound and other i2c functions do still work OK.
>>>
>>> While I always get this i2c_dw_xfer error on resume from suspend or hibernation on the T100TA,
>>> I also have a T100TAM and curiously, it NEVER shows that error -- although all the
>>> other suspend and hibernate behavior seems similar.  I'm not sure if the following could
>>> be the difference, but the T100TA uses an i2c connected ATML1000 touchscreen controller
>>> while the T100TAM uses an i2c connected SIS0817 touchscreen controller.  Other than that
>>> the hardware seems almost identical.
>>
>> I've been testing on an actual T100TA, with the ATML1000 touchscreen controller.
>>
>> Maybe it is a difference in BIOS version, my T100TA is running the latest BIOS, what
>> is the output of:
>>
>> cat /sys/class/dmi/id/bios_version /sys/class/dmi/id/bios_date
>>
> On the T100TA which shows the i2c_dw_xfer error the above cat reports:
> T100TA.307
> 05/09/2014
> 
> while the T100TA which does NOT show the i2c_dw_xfer error reports:
> T100TAM.205
> 07/25/2014
>>
>> Also do you perhaps have a microsd card inserted?  (I'm trying to figure out the
>> different between our setups so that I can hopefully reproduce the issue myself).
>>
> I do have a microsd card inserted in both the T100TA and the T100TAM.

Ah, ok I already suspected that and I think that is the difference between our
2 setups. I will try to reproduce the suspend/resume problem again with a microsd
card inserted and mounted.

>>> Regarding scripts, while I do still need a systemd hibernate script which removes the
>>> brcmfmac and the hci_uart (bluetooth related) drivers, I've found that I no longer need
>>> any script for suspend.
>>
>> Ok, so you are not doing any rmmod-s on suspend, right?
>>
> Correct -- I am NOT using a script and am not doing any explicit rmmod's on suspend, just on hibernate.
>> Regards,
>>
>> Hans
> 
> All my previous tests were done using a 5.1.0-rc5, 5.1.0-rc3, or earlier kernel.
> But I just compiled the released 5.1.0 kernel and the behavior has changed for the T100TA,
> resulting in a different i2c error and a call trace.  (I still continue to NOT see any
> suspend/resume errors on the T100TAM.)

This is expected we changed / improved the code generating the:
"i2c_designware 80860F41:00: Transfer while suspended"

Warning to include a trace, so that we know which code initiated the transfer,
which, as more or less expected, is the ACPI subsystem, like some power_on (_PS0)
or off (_PS3) method.

> Note that for all the tests described in this message I'm applying your patch
> regarding .poweroff_noirq and .restore_noirq, and I'm applying my own patch removing the
> DPM_FLAG_SMART_SUSPEND flag.  I haven't yet tried to explore varying those patches
> for the 5.1.0 release as I did for the earlier rc's, as described in previous messages.

Hmm, for future testing please leave out the patch removing the DPM_FLAG_SMART_SUSPEND
flag. Usually when asking you to test something we assume you are using a pristine kernel.
What does that patch attempt to fix and what happens during suspend/resume without it ?

Regards,

Hans