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

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Date:   Tue, 23 Apr 2019 10:07:40 +0200
From:   "Rafael J. Wysocki" <rafael@...nel.org>
To:     "Robert R. Howell" <RHowell@...o.edu>
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>
Subject: Re: [PATCH] ACPI / LPSS: Don't skip late system PM ops for hibernate
 on BYT/CHT

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 ?
> >>>
>
> > Still since my patch is regressing things for you I will try to
> > take a look at this and see if I can reproduce and come up with
> > a fix. But this is not going to be a high priority thing for me to
> > work on.
> >
> > In the mean time I've gone ahead and submitted my version of the
> > fix for the problem Kai-Heng was seeing, since that does not seem
> > to make your problem worse; and it will be good to get that problem
> > fixed.
> >
> > Regards,
> >
> > Hans
> >
>
> 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?