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Date:   Fri, 17 Apr 2020 16:43:40 +0200
From:   Andreas Kemnade <andreas@kemnade.info>
To:     "H. Nikolaus Schaller" <hns@goldelico.com>
Cc:     Tony Lindgren <tony@atomide.com>,
        Evgeniy Polyakov <zbr@ioremap.net>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-omap <linux-omap@vger.kernel.org>,
        Adam Ford <aford173@gmail.com>,
        "Andrew F . Davis" <afd@ti.com>, Vignesh R <vigneshr@ti.com>
Subject: Re: [PATCHv3] w1: omap-hdq: Simplify driver with PM runtime
 autosuspend
Message-ID: <20200417164340.3d9043d1@aktux>
In-Reply-To: <3197C3F0-DEB9-4221-AFBD-4F2A08C84C4C@goldelico.com>
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        <7B8C7DD9-095B-48FC-9642-695D07B79E97@goldelico.com>
        <20200416184638.GI37466@atomide.com>
        <3197C3F0-DEB9-4221-AFBD-4F2A08C84C4C@goldelico.com>
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On Fri, 17 Apr 2020 16:22:47 +0200
"H. Nikolaus Schaller" <hns@goldelico.com> wrote:

> > Am 16.04.2020 um 20:46 schrieb Tony Lindgren <tony@atomide.com>:
> >=20
> > * H. Nikolaus Schaller <hns@goldelico.com> [200416 15:04]: =20
> >> Hi Tony,
> >> it looks as if something with this patch is broken on GTA04. For v5.6 =
and v5.7-rc1.
> >>=20
> >> HDQ battery access times out after ca. 15 seconds and I get temperatur=
e of -273.1=C2=B0C...
> >>=20
> >> Reverting this patch and everything is ok again. =20
> >=20
> > Hmm OK interesting.
> >  =20
> >> What is "ti,mode" about? Do we have that (indirectly) in gta04.dtsi?
> >> Or does this patch need some CONFIGs we do not happen to have? =20
> >=20
> > Sounds like you have things working though so there should be no
> > need for having ti,mode =3D "1w" in the dts.
> >  =20
> >>> 	pm_runtime_enable(&pdev->dev);
> >>> +	pm_runtime_use_autosuspend(&pdev->dev);
> >>> +	pm_runtime_set_autosuspend_delay(&pdev->dev, 300); =20
> >=20
> > Care to check if changing pm_runtime_set_autosuspend_delay value
> > to -1 in probe makes the issue go away? Or change it manually
> > to -1 via sysfs.
> >=20
> > If that helps, likely we have a missing pm_runtime_get_sync()
> > somewhere in the driver. =20
>=20
> Yes, it does! It suffices to set it to -1 for one readout.
> Aything else I can test?
>=20
How does it depend on loaded drivers?
Is it really mainline kernel + config + devicetree or something else?

Can you reproduce the problem with init=3D/bin/bash
and then mount sysfs and modprobe omap_hdq?

Regarding pm_runtime stuff I thought I have the worst case scenario.

Regards,
Andreas