* Re: [PATCH v2 2/2] platform/x86: dell-*wmi*: Relay failed initial probe to dependent drivers
2017-11-09 17:49 ` [PATCH v2 2/2] platform/x86: dell-*wmi*: Relay failed initial probe to dependent drivers Mario Limonciello
@ 2017-11-09 18:51 ` sathyanarayanan kuppuswamy
2017-11-09 19:00 ` Mario.Limonciello
2017-11-09 23:44 ` Darren Hart
2017-11-09 23:47 ` Pali Rohár
2 siblings, 1 reply; 9+ messages in thread
From: sathyanarayanan kuppuswamy @ 2017-11-09 18:51 UTC (permalink / raw)
To: Mario Limonciello, dvhart, Andy Shevchenko
Cc: LKML, platform-driver-x86, pali.rohar
Hi,
On 11/09/2017 09:49 AM, Mario Limonciello wrote:
> dell-wmi and dell-smbios-wmi are dependent upon dell-wmi-descriptor
> finishing probe successfully to probe themselves.
if they are dependent, then why not control the device creation of
dell-wmi and dell-smbios-wmi drivers in del-wmi-descriptor probe ?
> Currently if dell-wmi-descriptor fails probing in a non-recoverable way
> (such as invalid header) dell-wmi and dell-smbios-wmi will continue to
> try to redo probing due to deferred probing.
>
> To solve this have the dependent drivers query the dell-wmi-descriptor
> driver whether the descriptor has been determined valid. The possible
> results are:
> -ENODEV: Descriptor GUID missing from WMI bus
> -EPROBE_DEFER: Descriptor not yet probed, dependent driver should wait
> and use deferred probing
> < 0: Descriptor probed, invalid. Dependent driver should return an
> error.
> 0: Successful descriptor probe, dependent driver can continue
>
> Successful descriptor probe still doesn't mean that the descriptor driver
> is necessarily bound at the time of initialization of dependent driver.
> Userspace can unbind the driver, so all methods used from driver
> should still be verified to return success values otherwise deferred
> probing be used.
>
> Signed-off-by: Mario Limonciello <mario.limonciello@dell.com>
> ---
> drivers/platform/x86/dell-smbios-wmi.c | 5 +++--
> drivers/platform/x86/dell-wmi-descriptor.c | 16 ++++++++++++++++
> drivers/platform/x86/dell-wmi-descriptor.h | 8 +++++++-
> drivers/platform/x86/dell-wmi.c | 6 ++++--
> 4 files changed, 30 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/platform/x86/dell-smbios-wmi.c b/drivers/platform/x86/dell-smbios-wmi.c
> index 35c13815b24c..ca556803c8c9 100644
> --- a/drivers/platform/x86/dell-smbios-wmi.c
> +++ b/drivers/platform/x86/dell-smbios-wmi.c
> @@ -148,8 +148,9 @@ static int dell_smbios_wmi_probe(struct wmi_device *wdev)
> int count;
> int ret;
>
> - if (!wmi_has_guid(DELL_WMI_DESCRIPTOR_GUID))
> - return -ENODEV;
> + ret = dell_wmi_get_descriptor_valid();
> + if (ret)
> + return ret;
>
> priv = devm_kzalloc(&wdev->dev, sizeof(struct wmi_smbios_priv),
> GFP_KERNEL);
> diff --git a/drivers/platform/x86/dell-wmi-descriptor.c b/drivers/platform/x86/dell-wmi-descriptor.c
> index 28ef5f37cfbf..4dfef1f53481 100644
> --- a/drivers/platform/x86/dell-wmi-descriptor.c
> +++ b/drivers/platform/x86/dell-wmi-descriptor.c
> @@ -21,14 +21,26 @@
> #include <linux/wmi.h>
> #include "dell-wmi-descriptor.h"
>
> +#define DELL_WMI_DESCRIPTOR_GUID "8D9DDCBC-A997-11DA-B012-B622A1EF5492"
> +
> struct descriptor_priv {
> struct list_head list;
> u32 interface_version;
> u32 size;
> };
> +static int descriptor_valid = -EPROBE_DEFER;
> static LIST_HEAD(wmi_list);
> static DEFINE_MUTEX(list_mutex);
>
> +int dell_wmi_get_descriptor_valid(void)
> +{
> + if (!wmi_has_guid(DELL_WMI_DESCRIPTOR_GUID))
> + return -ENODEV;
> +
> + return descriptor_valid;
> +}
> +EXPORT_SYMBOL_GPL(dell_wmi_get_descriptor_valid);
> +
> bool dell_wmi_get_interface_version(u32 *version)
> {
> struct descriptor_priv *priv;
> @@ -91,6 +103,7 @@ static int dell_wmi_descriptor_probe(struct wmi_device *wdev)
> if (obj->type != ACPI_TYPE_BUFFER) {
> dev_err(&wdev->dev, "Dell descriptor has wrong type\n");
> ret = -EINVAL;
> + descriptor_valid = ret;
> goto out;
> }
>
> @@ -102,6 +115,7 @@ static int dell_wmi_descriptor_probe(struct wmi_device *wdev)
> "Dell descriptor buffer has unexpected length (%d)\n",
> obj->buffer.length);
> ret = -EINVAL;
> + descriptor_valid = ret;
> goto out;
> }
>
> @@ -111,8 +125,10 @@ static int dell_wmi_descriptor_probe(struct wmi_device *wdev)
> dev_err(&wdev->dev, "Dell descriptor buffer has invalid signature (%8ph)\n",
> buffer);
> ret = -EINVAL;
> + descriptor_valid = ret;
> goto out;
> }
> + descriptor_valid = 0;
>
> if (buffer[2] != 0 && buffer[2] != 1)
> dev_warn(&wdev->dev, "Dell descriptor buffer has unknown version (%lu)\n",
> diff --git a/drivers/platform/x86/dell-wmi-descriptor.h b/drivers/platform/x86/dell-wmi-descriptor.h
> index 5f7b69c2c83a..1e8cb96ffd78 100644
> --- a/drivers/platform/x86/dell-wmi-descriptor.h
> +++ b/drivers/platform/x86/dell-wmi-descriptor.h
> @@ -13,7 +13,13 @@
>
> #include <linux/wmi.h>
>
> -#define DELL_WMI_DESCRIPTOR_GUID "8D9DDCBC-A997-11DA-B012-B622A1EF5492"
> +/* possible return values:
> + * -ENODEV: Descriptor GUID missing from WMI bus
> + * -EPROBE_DEFER: probing for dell-wmi-descriptor not yet run
> + * 0: valid descriptor, successfully probed
> + * < 0: invalid descriptor, don't probe dependent devices
> + */
> +int dell_wmi_get_descriptor_valid(void);
>
> bool dell_wmi_get_interface_version(u32 *version);
> bool dell_wmi_get_size(u32 *size);
> diff --git a/drivers/platform/x86/dell-wmi.c b/drivers/platform/x86/dell-wmi.c
> index 54321080a30d..39d2f4518483 100644
> --- a/drivers/platform/x86/dell-wmi.c
> +++ b/drivers/platform/x86/dell-wmi.c
> @@ -655,9 +655,11 @@ static int dell_wmi_events_set_enabled(bool enable)
> static int dell_wmi_probe(struct wmi_device *wdev)
> {
> struct dell_wmi_priv *priv;
> + int ret;
>
> - if (!wmi_has_guid(DELL_WMI_DESCRIPTOR_GUID))
> - return -ENODEV;
> + ret = dell_wmi_get_descriptor_valid();
> + if (ret)
> + return ret;
>
> priv = devm_kzalloc(
> &wdev->dev, sizeof(struct dell_wmi_priv), GFP_KERNEL);
--
Sathyanarayanan Kuppuswamy
Linux kernel developer
^ permalink raw reply [flat|nested] 9+ messages in thread* RE: [PATCH v2 2/2] platform/x86: dell-*wmi*: Relay failed initial probe to dependent drivers
2017-11-09 18:51 ` sathyanarayanan kuppuswamy
@ 2017-11-09 19:00 ` Mario.Limonciello
2017-11-09 22:33 ` sathyanarayanan kuppuswamy
0 siblings, 1 reply; 9+ messages in thread
From: Mario.Limonciello @ 2017-11-09 19:00 UTC (permalink / raw)
To: sathyanarayanan.kuppuswamy, dvhart, andy.shevchenko
Cc: linux-kernel, platform-driver-x86, pali.rohar
> -----Original Message-----
> From: platform-driver-x86-owner@vger.kernel.org [mailto:platform-driver-x86-
> owner@vger.kernel.org] On Behalf Of sathyanarayanan kuppuswamy
> Sent: Thursday, November 9, 2017 12:51 PM
> To: Limonciello, Mario <Mario_Limonciello@Dell.com>; dvhart@infradead.org;
> Andy Shevchenko <andy.shevchenko@gmail.com>
> Cc: LKML <linux-kernel@vger.kernel.org>; platform-driver-x86@vger.kernel.org;
> pali.rohar@gmail.com
> Subject: Re: [PATCH v2 2/2] platform/x86: dell-*wmi*: Relay failed initial probe to
> dependent drivers
>
> Hi,
>
>
> On 11/09/2017 09:49 AM, Mario Limonciello wrote:
> > dell-wmi and dell-smbios-wmi are dependent upon dell-wmi-descriptor
> > finishing probe successfully to probe themselves.
> if they are dependent, then why not control the device creation of
> dell-wmi and dell-smbios-wmi drivers in del-wmi-descriptor probe ?
The dependency is just in a function call that dell-wmi-descriptor provides
information to the other drivers.
Each of these is a driver that binds to a GUID on the WMI bus.
They can each be built/configured independently of one another and also
independently bound or unbound to a GUID on the WMI bus.
Since these are bus drivers, the WMI bus will control creation of devices
when probe routines are run.
>
> > Currently if dell-wmi-descriptor fails probing in a non-recoverable way
> > (such as invalid header) dell-wmi and dell-smbios-wmi will continue to
> > try to redo probing due to deferred probing.
> >
> > To solve this have the dependent drivers query the dell-wmi-descriptor
> > driver whether the descriptor has been determined valid. The possible
> > results are:
> > -ENODEV: Descriptor GUID missing from WMI bus
> > -EPROBE_DEFER: Descriptor not yet probed, dependent driver should wait
> > and use deferred probing
> > < 0: Descriptor probed, invalid. Dependent driver should return an
> > error.
> > 0: Successful descriptor probe, dependent driver can continue
> >
> > Successful descriptor probe still doesn't mean that the descriptor driver
> > is necessarily bound at the time of initialization of dependent driver.
> > Userspace can unbind the driver, so all methods used from driver
> > should still be verified to return success values otherwise deferred
> > probing be used.
> >
> > Signed-off-by: Mario Limonciello <mario.limonciello@dell.com>
> > ---
> > drivers/platform/x86/dell-smbios-wmi.c | 5 +++--
> > drivers/platform/x86/dell-wmi-descriptor.c | 16 ++++++++++++++++
> > drivers/platform/x86/dell-wmi-descriptor.h | 8 +++++++-
> > drivers/platform/x86/dell-wmi.c | 6 ++++--
> > 4 files changed, 30 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/platform/x86/dell-smbios-wmi.c b/drivers/platform/x86/dell-
> smbios-wmi.c
> > index 35c13815b24c..ca556803c8c9 100644
> > --- a/drivers/platform/x86/dell-smbios-wmi.c
> > +++ b/drivers/platform/x86/dell-smbios-wmi.c
> > @@ -148,8 +148,9 @@ static int dell_smbios_wmi_probe(struct wmi_device
> *wdev)
> > int count;
> > int ret;
> >
> > - if (!wmi_has_guid(DELL_WMI_DESCRIPTOR_GUID))
> > - return -ENODEV;
> > + ret = dell_wmi_get_descriptor_valid();
> > + if (ret)
> > + return ret;
> >
> > priv = devm_kzalloc(&wdev->dev, sizeof(struct wmi_smbios_priv),
> > GFP_KERNEL);
> > diff --git a/drivers/platform/x86/dell-wmi-descriptor.c
> b/drivers/platform/x86/dell-wmi-descriptor.c
> > index 28ef5f37cfbf..4dfef1f53481 100644
> > --- a/drivers/platform/x86/dell-wmi-descriptor.c
> > +++ b/drivers/platform/x86/dell-wmi-descriptor.c
> > @@ -21,14 +21,26 @@
> > #include <linux/wmi.h>
> > #include "dell-wmi-descriptor.h"
> >
> > +#define DELL_WMI_DESCRIPTOR_GUID "8D9DDCBC-A997-11DA-B012-
> B622A1EF5492"
> > +
> > struct descriptor_priv {
> > struct list_head list;
> > u32 interface_version;
> > u32 size;
> > };
> > +static int descriptor_valid = -EPROBE_DEFER;
> > static LIST_HEAD(wmi_list);
> > static DEFINE_MUTEX(list_mutex);
> >
> > +int dell_wmi_get_descriptor_valid(void)
> > +{
> > + if (!wmi_has_guid(DELL_WMI_DESCRIPTOR_GUID))
> > + return -ENODEV;
> > +
> > + return descriptor_valid;
> > +}
> > +EXPORT_SYMBOL_GPL(dell_wmi_get_descriptor_valid);
> > +
> > bool dell_wmi_get_interface_version(u32 *version)
> > {
> > struct descriptor_priv *priv;
> > @@ -91,6 +103,7 @@ static int dell_wmi_descriptor_probe(struct wmi_device
> *wdev)
> > if (obj->type != ACPI_TYPE_BUFFER) {
> > dev_err(&wdev->dev, "Dell descriptor has wrong type\n");
> > ret = -EINVAL;
> > + descriptor_valid = ret;
> > goto out;
> > }
> >
> > @@ -102,6 +115,7 @@ static int dell_wmi_descriptor_probe(struct wmi_device
> *wdev)
> > "Dell descriptor buffer has unexpected length (%d)\n",
> > obj->buffer.length);
> > ret = -EINVAL;
> > + descriptor_valid = ret;
> > goto out;
> > }
> >
> > @@ -111,8 +125,10 @@ static int dell_wmi_descriptor_probe(struct wmi_device
> *wdev)
> > dev_err(&wdev->dev, "Dell descriptor buffer has invalid signature
> (%8ph)\n",
> > buffer);
> > ret = -EINVAL;
> > + descriptor_valid = ret;
> > goto out;
> > }
> > + descriptor_valid = 0;
> >
> > if (buffer[2] != 0 && buffer[2] != 1)
> > dev_warn(&wdev->dev, "Dell descriptor buffer has unknown
> version (%lu)\n",
> > diff --git a/drivers/platform/x86/dell-wmi-descriptor.h
> b/drivers/platform/x86/dell-wmi-descriptor.h
> > index 5f7b69c2c83a..1e8cb96ffd78 100644
> > --- a/drivers/platform/x86/dell-wmi-descriptor.h
> > +++ b/drivers/platform/x86/dell-wmi-descriptor.h
> > @@ -13,7 +13,13 @@
> >
> > #include <linux/wmi.h>
> >
> > -#define DELL_WMI_DESCRIPTOR_GUID "8D9DDCBC-A997-11DA-B012-
> B622A1EF5492"
> > +/* possible return values:
> > + * -ENODEV: Descriptor GUID missing from WMI bus
> > + * -EPROBE_DEFER: probing for dell-wmi-descriptor not yet run
> > + * 0: valid descriptor, successfully probed
> > + * < 0: invalid descriptor, don't probe dependent devices
> > + */
> > +int dell_wmi_get_descriptor_valid(void);
> >
> > bool dell_wmi_get_interface_version(u32 *version);
> > bool dell_wmi_get_size(u32 *size);
> > diff --git a/drivers/platform/x86/dell-wmi.c b/drivers/platform/x86/dell-wmi.c
> > index 54321080a30d..39d2f4518483 100644
> > --- a/drivers/platform/x86/dell-wmi.c
> > +++ b/drivers/platform/x86/dell-wmi.c
> > @@ -655,9 +655,11 @@ static int dell_wmi_events_set_enabled(bool enable)
> > static int dell_wmi_probe(struct wmi_device *wdev)
> > {
> > struct dell_wmi_priv *priv;
> > + int ret;
> >
> > - if (!wmi_has_guid(DELL_WMI_DESCRIPTOR_GUID))
> > - return -ENODEV;
> > + ret = dell_wmi_get_descriptor_valid();
> > + if (ret)
> > + return ret;
> >
> > priv = devm_kzalloc(
> > &wdev->dev, sizeof(struct dell_wmi_priv), GFP_KERNEL);
>
> --
> Sathyanarayanan Kuppuswamy
> Linux kernel developer
^ permalink raw reply [flat|nested] 9+ messages in thread* Re: [PATCH v2 2/2] platform/x86: dell-*wmi*: Relay failed initial probe to dependent drivers
2017-11-09 19:00 ` Mario.Limonciello
@ 2017-11-09 22:33 ` sathyanarayanan kuppuswamy
0 siblings, 0 replies; 9+ messages in thread
From: sathyanarayanan kuppuswamy @ 2017-11-09 22:33 UTC (permalink / raw)
To: Mario.Limonciello, dvhart, andy.shevchenko
Cc: linux-kernel, platform-driver-x86, pali.rohar
Hi,
On 11/09/2017 11:00 AM, Mario.Limonciello@dell.com wrote:
>
>> -----Original Message-----
>> From: platform-driver-x86-owner@vger.kernel.org [mailto:platform-driver-x86-
>> owner@vger.kernel.org] On Behalf Of sathyanarayanan kuppuswamy
>> Sent: Thursday, November 9, 2017 12:51 PM
>> To: Limonciello, Mario <Mario_Limonciello@Dell.com>; dvhart@infradead.org;
>> Andy Shevchenko <andy.shevchenko@gmail.com>
>> Cc: LKML <linux-kernel@vger.kernel.org>; platform-driver-x86@vger.kernel.org;
>> pali.rohar@gmail.com
>> Subject: Re: [PATCH v2 2/2] platform/x86: dell-*wmi*: Relay failed initial probe to
>> dependent drivers
>>
>> Hi,
>>
>>
>> On 11/09/2017 09:49 AM, Mario Limonciello wrote:
>>> dell-wmi and dell-smbios-wmi are dependent upon dell-wmi-descriptor
>>> finishing probe successfully to probe themselves.
>> if they are dependent, then why not control the device creation of
>> dell-wmi and dell-smbios-wmi drivers in del-wmi-descriptor probe ?
> The dependency is just in a function call that dell-wmi-descriptor provides
> information to the other drivers.
Got it. Thanks for the clarification.
>
> Each of these is a driver that binds to a GUID on the WMI bus.
> They can each be built/configured independently of one another and also
> independently bound or unbound to a GUID on the WMI bus.
>
> Since these are bus drivers, the WMI bus will control creation of devices
> when probe routines are run.
>
>>> Currently if dell-wmi-descriptor fails probing in a non-recoverable way
>>> (such as invalid header) dell-wmi and dell-smbios-wmi will continue to
>>> try to redo probing due to deferred probing.
>>>
>>> To solve this have the dependent drivers query the dell-wmi-descriptor
>>> driver whether the descriptor has been determined valid. The possible
>>> results are:
>>> -ENODEV: Descriptor GUID missing from WMI bus
>>> -EPROBE_DEFER: Descriptor not yet probed, dependent driver should wait
>>> and use deferred probing
>>> < 0: Descriptor probed, invalid. Dependent driver should return an
>>> error.
>>> 0: Successful descriptor probe, dependent driver can continue
>>>
>>> Successful descriptor probe still doesn't mean that the descriptor driver
>>> is necessarily bound at the time of initialization of dependent driver.
>>> Userspace can unbind the driver, so all methods used from driver
>>> should still be verified to return success values otherwise deferred
>>> probing be used.
>>>
>>> Signed-off-by: Mario Limonciello <mario.limonciello@dell.com>
>>> ---
>>> drivers/platform/x86/dell-smbios-wmi.c | 5 +++--
>>> drivers/platform/x86/dell-wmi-descriptor.c | 16 ++++++++++++++++
>>> drivers/platform/x86/dell-wmi-descriptor.h | 8 +++++++-
>>> drivers/platform/x86/dell-wmi.c | 6 ++++--
>>> 4 files changed, 30 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/drivers/platform/x86/dell-smbios-wmi.c b/drivers/platform/x86/dell-
>> smbios-wmi.c
>>> index 35c13815b24c..ca556803c8c9 100644
>>> --- a/drivers/platform/x86/dell-smbios-wmi.c
>>> +++ b/drivers/platform/x86/dell-smbios-wmi.c
>>> @@ -148,8 +148,9 @@ static int dell_smbios_wmi_probe(struct wmi_device
>> *wdev)
>>> int count;
>>> int ret;
>>>
>>> - if (!wmi_has_guid(DELL_WMI_DESCRIPTOR_GUID))
>>> - return -ENODEV;
>>> + ret = dell_wmi_get_descriptor_valid();
>>> + if (ret)
>>> + return ret;
>>>
>>> priv = devm_kzalloc(&wdev->dev, sizeof(struct wmi_smbios_priv),
>>> GFP_KERNEL);
>>> diff --git a/drivers/platform/x86/dell-wmi-descriptor.c
>> b/drivers/platform/x86/dell-wmi-descriptor.c
>>> index 28ef5f37cfbf..4dfef1f53481 100644
>>> --- a/drivers/platform/x86/dell-wmi-descriptor.c
>>> +++ b/drivers/platform/x86/dell-wmi-descriptor.c
>>> @@ -21,14 +21,26 @@
>>> #include <linux/wmi.h>
>>> #include "dell-wmi-descriptor.h"
>>>
>>> +#define DELL_WMI_DESCRIPTOR_GUID "8D9DDCBC-A997-11DA-B012-
>> B622A1EF5492"
>>> +
>>> struct descriptor_priv {
>>> struct list_head list;
>>> u32 interface_version;
>>> u32 size;
>>> };
>>> +static int descriptor_valid = -EPROBE_DEFER;
>>> static LIST_HEAD(wmi_list);
>>> static DEFINE_MUTEX(list_mutex);
>>>
>>> +int dell_wmi_get_descriptor_valid(void)
>>> +{
>>> + if (!wmi_has_guid(DELL_WMI_DESCRIPTOR_GUID))
>>> + return -ENODEV;
>>> +
>>> + return descriptor_valid;
>>> +}
>>> +EXPORT_SYMBOL_GPL(dell_wmi_get_descriptor_valid);
>>> +
>>> bool dell_wmi_get_interface_version(u32 *version)
>>> {
>>> struct descriptor_priv *priv;
>>> @@ -91,6 +103,7 @@ static int dell_wmi_descriptor_probe(struct wmi_device
>> *wdev)
>>> if (obj->type != ACPI_TYPE_BUFFER) {
>>> dev_err(&wdev->dev, "Dell descriptor has wrong type\n");
>>> ret = -EINVAL;
>>> + descriptor_valid = ret;
>>> goto out;
>>> }
>>>
>>> @@ -102,6 +115,7 @@ static int dell_wmi_descriptor_probe(struct wmi_device
>> *wdev)
>>> "Dell descriptor buffer has unexpected length (%d)\n",
>>> obj->buffer.length);
>>> ret = -EINVAL;
>>> + descriptor_valid = ret;
>>> goto out;
>>> }
>>>
>>> @@ -111,8 +125,10 @@ static int dell_wmi_descriptor_probe(struct wmi_device
>> *wdev)
>>> dev_err(&wdev->dev, "Dell descriptor buffer has invalid signature
>> (%8ph)\n",
>>> buffer);
>>> ret = -EINVAL;
>>> + descriptor_valid = ret;
>>> goto out;
>>> }
>>> + descriptor_valid = 0;
>>>
>>> if (buffer[2] != 0 && buffer[2] != 1)
>>> dev_warn(&wdev->dev, "Dell descriptor buffer has unknown
>> version (%lu)\n",
>>> diff --git a/drivers/platform/x86/dell-wmi-descriptor.h
>> b/drivers/platform/x86/dell-wmi-descriptor.h
>>> index 5f7b69c2c83a..1e8cb96ffd78 100644
>>> --- a/drivers/platform/x86/dell-wmi-descriptor.h
>>> +++ b/drivers/platform/x86/dell-wmi-descriptor.h
>>> @@ -13,7 +13,13 @@
>>>
>>> #include <linux/wmi.h>
>>>
>>> -#define DELL_WMI_DESCRIPTOR_GUID "8D9DDCBC-A997-11DA-B012-
>> B622A1EF5492"
>>> +/* possible return values:
>>> + * -ENODEV: Descriptor GUID missing from WMI bus
>>> + * -EPROBE_DEFER: probing for dell-wmi-descriptor not yet run
>>> + * 0: valid descriptor, successfully probed
>>> + * < 0: invalid descriptor, don't probe dependent devices
>>> + */
>>> +int dell_wmi_get_descriptor_valid(void);
>>>
>>> bool dell_wmi_get_interface_version(u32 *version);
>>> bool dell_wmi_get_size(u32 *size);
>>> diff --git a/drivers/platform/x86/dell-wmi.c b/drivers/platform/x86/dell-wmi.c
>>> index 54321080a30d..39d2f4518483 100644
>>> --- a/drivers/platform/x86/dell-wmi.c
>>> +++ b/drivers/platform/x86/dell-wmi.c
>>> @@ -655,9 +655,11 @@ static int dell_wmi_events_set_enabled(bool enable)
>>> static int dell_wmi_probe(struct wmi_device *wdev)
>>> {
>>> struct dell_wmi_priv *priv;
>>> + int ret;
>>>
>>> - if (!wmi_has_guid(DELL_WMI_DESCRIPTOR_GUID))
>>> - return -ENODEV;
>>> + ret = dell_wmi_get_descriptor_valid();
>>> + if (ret)
>>> + return ret;
>>>
>>> priv = devm_kzalloc(
>>> &wdev->dev, sizeof(struct dell_wmi_priv), GFP_KERNEL);
>> --
>> Sathyanarayanan Kuppuswamy
>> Linux kernel developer
--
Sathyanarayanan Kuppuswamy
Linux kernel developer
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH v2 2/2] platform/x86: dell-*wmi*: Relay failed initial probe to dependent drivers
2017-11-09 17:49 ` [PATCH v2 2/2] platform/x86: dell-*wmi*: Relay failed initial probe to dependent drivers Mario Limonciello
2017-11-09 18:51 ` sathyanarayanan kuppuswamy
@ 2017-11-09 23:44 ` Darren Hart
2017-11-09 23:47 ` Pali Rohár
2 siblings, 0 replies; 9+ messages in thread
From: Darren Hart @ 2017-11-09 23:44 UTC (permalink / raw)
To: Mario Limonciello; +Cc: Andy Shevchenko, LKML, platform-driver-x86, pali.rohar
On Thu, Nov 09, 2017 at 11:49:10AM -0600, Mario Limonciello wrote:
> dell-wmi and dell-smbios-wmi are dependent upon dell-wmi-descriptor
> finishing probe successfully to probe themselves.
>
> Currently if dell-wmi-descriptor fails probing in a non-recoverable way
> (such as invalid header) dell-wmi and dell-smbios-wmi will continue to
> try to redo probing due to deferred probing.
>
> To solve this have the dependent drivers query the dell-wmi-descriptor
> driver whether the descriptor has been determined valid. The possible
> results are:
> -ENODEV: Descriptor GUID missing from WMI bus
> -EPROBE_DEFER: Descriptor not yet probed, dependent driver should wait
> and use deferred probing
> < 0: Descriptor probed, invalid. Dependent driver should return an
> error.
> 0: Successful descriptor probe, dependent driver can continue
>
> Successful descriptor probe still doesn't mean that the descriptor driver
> is necessarily bound at the time of initialization of dependent driver.
> Userspace can unbind the driver, so all methods used from driver
> should still be verified to return success values otherwise deferred
> probing be used.
This is a good improvement. Will give Pali a chance to offer his signature, and
will merge then.
--
Darren Hart
VMware Open Source Technology Center
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH v2 2/2] platform/x86: dell-*wmi*: Relay failed initial probe to dependent drivers
2017-11-09 17:49 ` [PATCH v2 2/2] platform/x86: dell-*wmi*: Relay failed initial probe to dependent drivers Mario Limonciello
2017-11-09 18:51 ` sathyanarayanan kuppuswamy
2017-11-09 23:44 ` Darren Hart
@ 2017-11-09 23:47 ` Pali Rohár
2 siblings, 0 replies; 9+ messages in thread
From: Pali Rohár @ 2017-11-09 23:47 UTC (permalink / raw)
To: Mario Limonciello; +Cc: dvhart, Andy Shevchenko, LKML, platform-driver-x86
On Thursday 09 November 2017 11:49:10 Mario Limonciello wrote:
> dell-wmi and dell-smbios-wmi are dependent upon dell-wmi-descriptor
> finishing probe successfully to probe themselves.
>
> Currently if dell-wmi-descriptor fails probing in a non-recoverable way
> (such as invalid header) dell-wmi and dell-smbios-wmi will continue to
> try to redo probing due to deferred probing.
>
> To solve this have the dependent drivers query the dell-wmi-descriptor
> driver whether the descriptor has been determined valid. The possible
> results are:
> -ENODEV: Descriptor GUID missing from WMI bus
> -EPROBE_DEFER: Descriptor not yet probed, dependent driver should wait
> and use deferred probing
> < 0: Descriptor probed, invalid. Dependent driver should return an
> error.
> 0: Successful descriptor probe, dependent driver can continue
>
> Successful descriptor probe still doesn't mean that the descriptor driver
> is necessarily bound at the time of initialization of dependent driver.
> Userspace can unbind the driver, so all methods used from driver
> should still be verified to return success values otherwise deferred
> probing be used.
>
> Signed-off-by: Mario Limonciello <mario.limonciello@dell.com>
> ---
> drivers/platform/x86/dell-smbios-wmi.c | 5 +++--
> drivers/platform/x86/dell-wmi-descriptor.c | 16 ++++++++++++++++
> drivers/platform/x86/dell-wmi-descriptor.h | 8 +++++++-
> drivers/platform/x86/dell-wmi.c | 6 ++++--
> 4 files changed, 30 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/platform/x86/dell-smbios-wmi.c b/drivers/platform/x86/dell-smbios-wmi.c
> index 35c13815b24c..ca556803c8c9 100644
> --- a/drivers/platform/x86/dell-smbios-wmi.c
> +++ b/drivers/platform/x86/dell-smbios-wmi.c
> @@ -148,8 +148,9 @@ static int dell_smbios_wmi_probe(struct wmi_device *wdev)
> int count;
> int ret;
>
> - if (!wmi_has_guid(DELL_WMI_DESCRIPTOR_GUID))
> - return -ENODEV;
> + ret = dell_wmi_get_descriptor_valid();
> + if (ret)
> + return ret;
>
> priv = devm_kzalloc(&wdev->dev, sizeof(struct wmi_smbios_priv),
> GFP_KERNEL);
> diff --git a/drivers/platform/x86/dell-wmi-descriptor.c b/drivers/platform/x86/dell-wmi-descriptor.c
> index 28ef5f37cfbf..4dfef1f53481 100644
> --- a/drivers/platform/x86/dell-wmi-descriptor.c
> +++ b/drivers/platform/x86/dell-wmi-descriptor.c
> @@ -21,14 +21,26 @@
> #include <linux/wmi.h>
> #include "dell-wmi-descriptor.h"
>
> +#define DELL_WMI_DESCRIPTOR_GUID "8D9DDCBC-A997-11DA-B012-B622A1EF5492"
> +
> struct descriptor_priv {
> struct list_head list;
> u32 interface_version;
> u32 size;
> };
> +static int descriptor_valid = -EPROBE_DEFER;
> static LIST_HEAD(wmi_list);
> static DEFINE_MUTEX(list_mutex);
>
> +int dell_wmi_get_descriptor_valid(void)
> +{
> + if (!wmi_has_guid(DELL_WMI_DESCRIPTOR_GUID))
> + return -ENODEV;
> +
> + return descriptor_valid;
> +}
> +EXPORT_SYMBOL_GPL(dell_wmi_get_descriptor_valid);
> +
> bool dell_wmi_get_interface_version(u32 *version)
> {
> struct descriptor_priv *priv;
> @@ -91,6 +103,7 @@ static int dell_wmi_descriptor_probe(struct wmi_device *wdev)
> if (obj->type != ACPI_TYPE_BUFFER) {
> dev_err(&wdev->dev, "Dell descriptor has wrong type\n");
> ret = -EINVAL;
> + descriptor_valid = ret;
> goto out;
> }
>
> @@ -102,6 +115,7 @@ static int dell_wmi_descriptor_probe(struct wmi_device *wdev)
> "Dell descriptor buffer has unexpected length (%d)\n",
> obj->buffer.length);
> ret = -EINVAL;
> + descriptor_valid = ret;
> goto out;
> }
>
> @@ -111,8 +125,10 @@ static int dell_wmi_descriptor_probe(struct wmi_device *wdev)
> dev_err(&wdev->dev, "Dell descriptor buffer has invalid signature (%8ph)\n",
> buffer);
> ret = -EINVAL;
> + descriptor_valid = ret;
> goto out;
> }
> + descriptor_valid = 0;
>
> if (buffer[2] != 0 && buffer[2] != 1)
> dev_warn(&wdev->dev, "Dell descriptor buffer has unknown version (%lu)\n",
> diff --git a/drivers/platform/x86/dell-wmi-descriptor.h b/drivers/platform/x86/dell-wmi-descriptor.h
> index 5f7b69c2c83a..1e8cb96ffd78 100644
> --- a/drivers/platform/x86/dell-wmi-descriptor.h
> +++ b/drivers/platform/x86/dell-wmi-descriptor.h
> @@ -13,7 +13,13 @@
>
> #include <linux/wmi.h>
>
> -#define DELL_WMI_DESCRIPTOR_GUID "8D9DDCBC-A997-11DA-B012-B622A1EF5492"
> +/* possible return values:
> + * -ENODEV: Descriptor GUID missing from WMI bus
> + * -EPROBE_DEFER: probing for dell-wmi-descriptor not yet run
> + * 0: valid descriptor, successfully probed
> + * < 0: invalid descriptor, don't probe dependent devices
> + */
> +int dell_wmi_get_descriptor_valid(void);
>
> bool dell_wmi_get_interface_version(u32 *version);
> bool dell_wmi_get_size(u32 *size);
> diff --git a/drivers/platform/x86/dell-wmi.c b/drivers/platform/x86/dell-wmi.c
> index 54321080a30d..39d2f4518483 100644
> --- a/drivers/platform/x86/dell-wmi.c
> +++ b/drivers/platform/x86/dell-wmi.c
> @@ -655,9 +655,11 @@ static int dell_wmi_events_set_enabled(bool enable)
> static int dell_wmi_probe(struct wmi_device *wdev)
> {
> struct dell_wmi_priv *priv;
> + int ret;
>
> - if (!wmi_has_guid(DELL_WMI_DESCRIPTOR_GUID))
> - return -ENODEV;
> + ret = dell_wmi_get_descriptor_valid();
> + if (ret)
> + return ret;
>
> priv = devm_kzalloc(
> &wdev->dev, sizeof(struct dell_wmi_priv), GFP_KERNEL);
Looks good,
Reviewed-by: Pali Rohár <pali.rohar@gmail.com>
--
Pali Rohár
pali.rohar@gmail.com
^ permalink raw reply [flat|nested] 9+ messages in thread