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

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Date:   Wed, 26 Sep 2018 20:02:31 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Mario Limonciello <mario.limonciello@...l.com>
Cc:     Darren Hart <dvhart@...radead.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Platform Driver <platform-driver-x86@...r.kernel.org>,
        Mika Westerberg <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.

>
> 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