RE: [PATCH v3] Add driver to force WMI Thunderbolt controller power status

From	<Mario.Limonciello@dell.com>
Newsgroups	linux.kernel
Subject	RE: [PATCH v3] Add driver to force WMI Thunderbolt controller power status
Date	2017-09-14 17:00 +0200
Message-ID	<upDMu-6ln-29@gated-at.bofh.it> (permalink)
References	<untoe-qu-21@gated-at.bofh.it> <upjE5-1RR-7@gated-at.bofh.it> <upx4n-293-11@gated-at.bofh.it> <upyD7-3bN-17@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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> -----Original Message-----
> From: Lukas Wunner [mailto:lukas@wunner.de]
> Sent: Thursday, September 14, 2017 4:14 AM
> To: Limonciello, Mario <Mario_Limonciello@Dell.com>
> Cc: dvhart@infradead.org; linux-kernel@vger.kernel.org; platform-driver-
> x86@vger.kernel.org; hughsient@gmail.com; yehezkelshb@gmail.com;
> mika.westerberg@linux.intel.com
> Subject: Re: [PATCH v3] Add driver to force WMI Thunderbolt controller power
> status
> 
> On Thu, Sep 14, 2017 at 06:42:03AM +0000, Mario.Limonciello@dell.com wrote:
> > > On Fri, Sep 08, 2017 at 10:23:11AM -0500, Mario Limonciello wrote:
> > > > +static const struct wmi_device_id intel_wmi_thunderbolt_id_table[] = {
> > > > +	{ .guid_string = INTEL_WMI_THUNDERBOLT_GUID },
> > > > +	{ },
> > > > +};
> > >
> > > I'm not familiar with WMI, but don't you need a MODULE_DEVICE_TABLE here?
> > > How does user space know which module to load upon receiving the uevent?
> >
> > Some macros for WMI bus devices.
> >
> https://github.com/torvalds/linux/blob/e0f25a3f2d052e36ff67a9b4db835c3e27e9
> 50d8/include/linux/wmi.h#L55
> > https://github.com/torvalds/linux/blob/master/include/linux/device.h#L1487
> 
> No, the init and exit hooks defined by this macro are executed
> *after* the module has been loaded.  The question was, how does
> the module get loaded in the first place?
> 
> Looking at drivers/platform/x86/wmi.c:wmi_dev_uevent() it seems that
> a modalias consisting of "wmi:" followed by the GUID is sent to udevd.
> For udevd to then load the module, I suspect you need to add a
> MODULE_DEVICE_TABLE(wmi, ...) to your driver.

Ah, you're looking for this code from the WMI bus driver:
https://github.com/torvalds/linux/blob/master/drivers/platform/x86/wmi.c#L724

That happens when the bus is initialized.

Thread

Re: [PATCH v3] Add driver to force WMI Thunderbolt controller power  status Lukas Wunner <lukas@wunner.de> - 2017-09-13 19:30 +0200
  RE: [PATCH v3] Add driver to force WMI Thunderbolt controller power  status <Mario.Limonciello@dell.com> - 2017-09-14 09:50 +0200
    Re: [PATCH v3] Add driver to force WMI Thunderbolt controller power  status Lukas Wunner <lukas@wunner.de> - 2017-09-14 11:30 +0200
      RE: [PATCH v3] Add driver to force WMI Thunderbolt controller power  status <Mario.Limonciello@dell.com> - 2017-09-14 17:00 +0200
        Re: [PATCH v3] Add driver to force WMI Thunderbolt controller power  status Mika Westerberg <mika.westerberg@linux.intel.com> - 2017-09-14 17:10 +0200
          Re: [PATCH v3] Add driver to force WMI Thunderbolt controller power  status Mika Westerberg <mika.westerberg@linux.intel.com> - 2017-09-14 17:20 +0200
          Re: [PATCH v3] Add driver to force WMI Thunderbolt controller power  status Lukas Wunner <lukas@wunner.de> - 2017-09-15 09:50 +0200
            RE: [PATCH v3] Add driver to force WMI Thunderbolt controller power  status <Mario.Limonciello@dell.com> - 2017-09-15 18:40 +0200

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