linux-kernel - RE: [PATCH] platform/x86: intel-wmi-thunderbolt: Add dynamic debugging

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Date:   Wed, 26 Sep 2018 17:03:45 +0000
From:   <Mario.Limonciello@...l.com>
To:     <andy.shevchenko@...il.com>
CC:     <dvhart@...radead.org>, <linux-kernel@...r.kernel.org>,
        <platform-driver-x86@...r.kernel.org>, <mika.westerberg@...el.com>
Subject: RE: [PATCH] platform/x86: intel-wmi-thunderbolt: Add dynamic
 debugging

> 
> On Wed, Sep 26, 2018 at 7:11 PM Mario Limonciello
> <mario.limonciello@...l.com> wrote:
> >
> > Some users have been reporting issues with thunderbolt being turned off
> > before fully initialized.  This is suspected to be caused by userspace
> > turning off the Thunderbolt controller using intel-wmi-thunderbolt
> > prematurely.
> >
> 
> > Details are available here:
> > https://bugzilla.kernel.org/show_bug.cgi?id=201227
> > https://bugzilla.kernel.org/show_bug.cgi?id=199631
> 
> BugLink: ... ?
> BugLink: ... ?
> 
> I can do it myself if you are okay with this format.
> 
> The patch itself LGTM.

Sure, thank you.

> 
> >
> > Userspace has already made some mitigiations for this situation:
> > https://github.com/hughsie/fwupd/commit/ef6f1d76983c9b66
> > https://github.com/hughsie/fwupd/commit/c07ce5b4889a5384
> >
> > To allow easier debugging of this situation add output that can be turned
> > on with dynamic debugging to better root cause this problem.
> >
> > Suggested-by: Mika Westerberg <mika.westerberg@...el.com>
> > Signed-off-by: Mario Limonciello <mario.limonciello@...l.com>
> > ---
> >  drivers/platform/x86/intel-wmi-thunderbolt.c | 6 +++++-
> >  1 file changed, 5 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/platform/x86/intel-wmi-thunderbolt.c
> b/drivers/platform/x86/intel-wmi-thunderbolt.c
> > index c2257bd..ce5fbf0 100644
> > --- a/drivers/platform/x86/intel-wmi-thunderbolt.c
> > +++ b/drivers/platform/x86/intel-wmi-thunderbolt.c
> > @@ -38,12 +38,16 @@ static ssize_t force_power_store(struct device *dev,
> >         input.length = sizeof(u8);
> >         input.pointer = &mode;
> >         mode = hex_to_bin(buf[0]);
> > +       dev_dbg(dev, "force_power: storing %#x\n", mode);
> >         if (mode == 0 || mode == 1) {
> >                 status = wmi_evaluate_method(INTEL_WMI_THUNDERBOLT_GUID, 0, 1,
> >                                              &input, NULL);
> > -               if (ACPI_FAILURE(status))
> > +               if (ACPI_FAILURE(status)) {
> > +                       dev_dbg(dev, "force_power: failed to evaluate ACPI method\n");
> >                         return -ENODEV;
> > +               }
> >         } else {
> > +               dev_dbg(dev, "force_power: unsupported mode\n");
> >                 return -EINVAL;
> >         }
> >         return count;
> > --
> > 2.7.4
> >
> 
> 
> --
> With Best Regards,
> Andy Shevchenko