lkml.org 
[lkml]   [2017]   [Oct]   [31]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [PATCH v11 05/15] platform/x86: dell-wmi-descriptor: split WMI descriptor into it's own driver
On Mon, Oct 30, 2017 at 01:32:57PM +0000, Mario.Limonciello@dell.com wrote:
>
>
> > -----Original Message-----
> > From: Pali Rohár [mailto:pali.rohar@gmail.com]
> > Sent: Monday, October 30, 2017 6:47 AM
> > To: Limonciello, Mario <Mario_Limonciello@Dell.com>
> > Cc: dvhart@infradead.org; Andy Shevchenko <andy.shevchenko@gmail.com>;
> > LKML <linux-kernel@vger.kernel.org>; platform-driver-x86@vger.kernel.org; Andy
> > Lutomirski <luto@kernel.org>; quasisec@google.com; rjw@rjwysocki.net;
> > mjg59@google.com; hch@lst.de; Greg KH <greg@kroah.com>; Alan Cox
> > <gnomes@lxorguk.ukuu.org.uk>
> > Subject: Re: [PATCH v11 05/15] platform/x86: dell-wmi-descriptor: split WMI
> > descriptor into it's own driver
> >
> > On Friday 20 October 2017 12:40:20 Mario Limonciello wrote:
> > > diff --git a/drivers/platform/x86/dell-wmi-descriptor.c
> > b/drivers/platform/x86/dell-wmi-descriptor.c
> > > new file mode 100644
> > > index 000000000000..3204c408e261
> > > --- /dev/null
> > > +++ b/drivers/platform/x86/dell-wmi-descriptor.c
> >
> > This dell-wmi-descriptor.c looks good now!
> >
> > > diff --git a/drivers/platform/x86/dell-wmi-descriptor.h
> > b/drivers/platform/x86/dell-wmi-descriptor.h
> > > new file mode 100644
> > > index 000000000000..5f7b69c2c83a
> > > --- /dev/null
> > > +++ b/drivers/platform/x86/dell-wmi-descriptor.h
> > > @@ -721,7 +652,9 @@ static int dell_wmi_events_set_enabled(bool enable)
> > > static int dell_wmi_probe(struct wmi_device *wdev)
> > > {
> > > struct dell_wmi_priv *priv;
> > > - int err;
> > > +
> > > + if (!wmi_has_guid(DELL_WMI_DESCRIPTOR_GUID))
> > > + return -ENODEV;
> > >
> > > priv = devm_kzalloc(
> > > &wdev->dev, sizeof(struct dell_wmi_priv), GFP_KERNEL);
> > > @@ -729,9 +662,8 @@ static int dell_wmi_probe(struct wmi_device *wdev)
> > > return -ENOMEM;
> > > dev_set_drvdata(&wdev->dev, priv);
> > >
> > > - err = dell_wmi_check_descriptor_buffer(wdev);
> > > - if (err)
> > > - return err;
> > > + if (!dell_wmi_get_interface_version(&priv->interface_version))
> > > + return -EPROBE_DEFER;
> >
> > But here is still a problem. You added check that
> > DELL_WMI_DESCRIPTOR_GUID exists in APCI table, but it does not mean that
> > probe method of dell-wmi-descriptor cannot fail.
> >
> > With PROBE_DEFER, dell_wmi_probe function would be called later again
> > and again, even when probing dell-wmi-descriptor failed and so dell-wmi
> > in this case cannot work.
> >
>
> Yes it's possible that probe method can fail, but it depends on the reason for
> failure if it will fail again later. For example if not enough memory, it may work
> later. Or maybe user manually unbound from GUID, should continue to try until
> it's bound again.
>
> So in short, I believe this is the correct behavior to adopt.

In this case, I believe the synchronous request_module("dell-wmi-descriptor")
would provide the desired result. The exit status doesn't even need to be
checked. If that is successful, and the interface_version still returns false,
then it can be considered an error and we can exit. If it fails, the
interface_version will return false, and it is also an error.

This can be easily added as a single patch on top of this series:

diff --git a/drivers/platform/x86/dell-wmi.c b/drivers/platform/x86/dell-wmi.c
index dcfa5de..964ca54 100644
--- a/drivers/platform/x86/dell-wmi.c
+++ b/drivers/platform/x86/dell-wmi.c
@@ -665,8 +665,9 @@ static int dell_wmi_probe(struct wmi_device *wdev)
return -ENOMEM;
dev_set_drvdata(&wdev->dev, priv);

+ request_module("dell-wmi-descriptor");
if (!dell_wmi_get_interface_version(&priv->interface_version))
- return -EPROBE_DEFER;
+ return -ENODEV;

return dell_wmi_input_setup(wdev);
}
Pali, I believe this addresses your concern?

--
Darren Hart
VMware Open Source Technology Center

\
 
 \ /
  Last update: 2017-11-01 00:33    [W:0.101 / U:0.580 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site