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From:   "Rafael J. Wysocki" <rafael@kernel.org>
Date:   Wed, 24 Apr 2019 09:20:28 +0200
Message-ID: <CAJZ5v0jJEovXXiqs-tzPC7FsGjGL+qxfXCxbTrQZqAxSCv1oyQ@mail.gmail.com>
Subject: Re: [PATCH] ACPI / LPSS: Don't skip late system PM ops for hibernate
 on BYT/CHT
To:     "Robert R. Howell" <RHowell@uwyo.edu>
Cc:     "Rafael J. Wysocki" <rafael@kernel.org>,
        Hans de Goede <hdegoede@redhat.com>,
        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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On Tue, Apr 23, 2019 at 10:03 PM Robert R. Howell <RHowell@uwyo.edu> wrote:
>
> On 4/23/19 2:07 AM, Rafael J. Wysocki wrote:
> >
> > On Sat, Apr 20, 2019 at 12:44 AM Robert R. Howell <RHowell@uwyo.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.

OK, thanks!

Is non-hibernation system suspend affected too?