linux-kernel - Re: [PATCH] pinctrl: intel: save HOSTSW

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Date:   Wed, 27 Mar 2019 19:29:40 +0200
From:   Mika Westerberg <mika.westerberg@...ux.intel.com>
To:     Daniel Drake <drake@...lessm.com>
Cc:     Chris Chiu <chiu@...lessm.com>,
        Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        "open list:PIN CONTROL SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        Linux Kernel <linux-kernel@...r.kernel.org>,
        Linux Upstreaming Team <linux@...lessm.com>,
        Andy Shevchenko <andriy.shevchenko@...el.com>
Subject: Re: [PATCH] pinctrl: intel: save HOSTSW_OWN register over
 suspend/resume

+Andy

On Wed, Mar 27, 2019 at 04:22:04PM +0800, Daniel Drake wrote:
> Hi Mika,
> 
> Digging up this old thread again...
> 
> On Tue, Nov 21, 2017 at 8:13 PM Mika Westerberg
> <mika.westerberg@...ux.intel.com> wrote:
> >
> > On Tue, Nov 21, 2017 at 07:54:26PM +0800, Chris Chiu wrote:
> > > Yup, I checked the value of the corresponded pin. It shows following before
> > > suspend
> > > pin 18 (GPIO_18) GPIO 0x40800102 0x00024075
> > >
> > > Then after resume
> > > pin 18 (GPIO_18) GPIO 0x40800102 0x00024075 [ACPI]
> >
> > OK, so ownership is changed to ACPI.
> >
> > > What else register do you suggest me to compare? The PADCFG2 is invalid
> >
> > It's fine APL does not have PADCFG2.
> >
> > Hmm, I don't understand how this can work in Windows either. The Windows
> > people told me that they don't save and restore anything else than
> > padcfg registers + ie. If the ownership is changed to ACPI it means you
> > don't get interrupts anymore (only GPEs) and that applies to Windows as
> > well.
> 
> In the mails after the one quoted above, we reported back to you that
> the new BIOS from Asus solved the issue.
> 
> However, during the time that has followed, we have had numerous user
> reports from Asus E403NA, X540NA, and X541NA laptops (basically the
> same models that we originally discussed) where the touchpad stops
> working after suspend/resume, even with the latest BIOS. We managed to
> get an affected E403NA unit in-hands again, and confirmed that
> HOSTSW_OWN was being lost like we had observed before.
> 
> Unfortunately as this was a customer laptop we had to return it
> immediately, before we could investigate further. We don't have access
> to any more units since they are old models now.
> 
> However I'm wondering if you have any other ideas or if you think
> something like our workaround patch might be acceptable under these
> circumstances:
> https://github.com/endlessm/linux/commit/f391452299f62a3d0cbe5333be90f69e9895d8ff

I wonder if it would be simpler to save it always and then upon resume
compare them and if changed, log this in dmesg and restore the saved
one.