linux-kernel - Re: [PATCH] ACPI / LPSS: Don't skip late system PM ops for hibernate on BYT/CHT

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Message-ID: <144b56d4-54e6-bccd-4652-22303bcd9168@uwyo.edu>
Date:   Tue, 23 Apr 2019 20:03:08 +0000
From:   "Robert R. Howell" <RHowell@...o.edu>
To:     "Rafael J. Wysocki" <rafael@...nel.org>
CC:     Hans de Goede <hdegoede@...hat.com>,
        Kai-Heng Feng <kai.heng.feng@...onical.com>,
        "rjw@...ysocki.net" <rjw@...ysocki.net>,
        "lenb@...nel.org" <lenb@...nel.org>,
        "linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "Robert R. Howell" <RHowell@...o.edu>
Subject: Re: [PATCH] ACPI / LPSS: Don't skip late system PM ops for hibernate
 on BYT/CHT

On 4/23/19 2:07 AM, Rafael J. Wysocki wrote:
> 
> On Sat, Apr 20, 2019 at 12:44 AM Robert R. Howell <RHowell@...o.edu> wrote:
>>
>> On 4/18/19 5:42 AM, Hans de Goede wrote:
>>
>>>> On 4/8/19 2:16 AM, Hans de Goede wrote:>
>>>>>
>>>>> Hmm, interesting so you have hibernation working on a T100TA
>>>>> (with 5.0 + 02e45646d53b reverted), right ?
>>>>>
>>
>>
>> I've managed to find a way around the i2c_designware timeout issues
>> on the T100TA's.  The key is to NOT set DPM_FLAG_SMART_SUSPEND,
>> which was added in the 02e45646d53b commit.
>>
>> To test that I've started with a 5.1-rc5 kernel, applied your recent patch
>> to acpi_lpss.c, then apply the following patch of mine, removing
>> DPM_FLAG_SMART_SUSPEND.  (For the T100 hardware I need to apply some
>> other patches as well but those are not related to the i2c-designware or
>> acpi issues addressed here.)
>>
>> On a resume from hibernation I still see one error:
>>   "i2c_designware 80860F41:00: Error i2c_dw_xfer called while suspended"
>> but I no longer get the i2c_designware timeouts, and audio does now work
>> after the resume.
>>
>> Removing DPM_FLAG_SMART_SUSPEND may not be what you want for other
>> hardware, but perhaps this will give you a clue as to what is going
>> wrong with hibernate/resume on the T100TA's.
> 
> What if you drop DPM_FLAG_LEAVE_SUSPENDED alone instead?
> 

I did try dropping just DPM_FLAG_LEAVE_SUSPENDED, dropping just 
DPM_FLAG_SMART_SUSPEND, and dropping both flags.  When I just drop 
DPM_FLAG_LEAVE_SUSPENDED I still get the i2c_designware timeouts 
after the resume.  If I drop just DPM_FLAG_SMART_SUSPEND or drop both, 
then the timeouts go away.

Bob Howell