[PATCH v2 1/2] platform/x86: dell-ddv: Fix cache invalidation on resume

[PATCH v2 1/2] platform/x86: dell-ddv: Fix cache invalidation on resume

[Armin Wolf]

If one or both sensor buffers could not be initialized, either
due to missing hardware support or due to some error during probing,
the resume handler will encounter undefined behaviour when
attempting to lock buffers then protected by an uninitialized or
destroyed mutex.
Fix this by introducing a "active" flag which is set during probe,
and only invalidate buffers which where flaged as "active".

Tested on a Dell Inspiron 3505.

Fixes: 3b7eeff93d29 ("platform/x86: dell-ddv: Add hwmon support")
Signed-off-by: Armin Wolf <W_Armin@gmx.de>
---
Changes in v2:
- move checking of the "active" flag inside
  dell_wmi_ddv_hwmon_cache_invalidate()
---
 drivers/platform/x86/dell/dell-wmi-ddv.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/platform/x86/dell/dell-wmi-ddv.c b/drivers/platform/x86/dell/dell-wmi-ddv.c
index d547c9d09725..eff4e9649faf 100644
--- a/drivers/platform/x86/dell/dell-wmi-ddv.c
+++ b/drivers/platform/x86/dell/dell-wmi-ddv.c
@@ -96,6 +96,7 @@ struct combined_chip_info {
 };

 struct dell_wmi_ddv_sensors {
+	bool active;
 	struct mutex lock;	/* protect caching */
 	unsigned long timestamp;
 	union acpi_object *obj;
@@ -520,6 +521,9 @@ static struct hwmon_channel_info *dell_wmi_ddv_channel_create(struct device *dev

 static void dell_wmi_ddv_hwmon_cache_invalidate(struct dell_wmi_ddv_sensors *sensors)
 {
+	if (!sensors->active)
+		return;
+
 	mutex_lock(&sensors->lock);
 	kfree(sensors->obj);
 	sensors->obj = NULL;
@@ -530,6 +534,7 @@ static void dell_wmi_ddv_hwmon_cache_destroy(void *data)
 {
 	struct dell_wmi_ddv_sensors *sensors = data;

+	sensors->active = false;
 	mutex_destroy(&sensors->lock);
 	kfree(sensors->obj);
 }
@@ -549,6 +554,7 @@ static struct hwmon_channel_info *dell_wmi_ddv_channel_init(struct wmi_device *w
 		return ERR_PTR(ret);

 	mutex_init(&sensors->lock);
+	sensors->active = true;

 	ret = devm_add_action_or_reset(&wdev->dev, dell_wmi_ddv_hwmon_cache_destroy, sensors);
 	if (ret < 0)
@@ -852,7 +858,7 @@ static int dell_wmi_ddv_resume(struct device *dev)
 {
 	struct dell_wmi_ddv_data *data = dev_get_drvdata(dev);

-	/* Force re-reading of all sensors */
+	/* Force re-reading of all active sensors */
 	dell_wmi_ddv_hwmon_cache_invalidate(&data->fans);
 	dell_wmi_ddv_hwmon_cache_invalidate(&data->temps);

--
2.30.2

[PATCH v2 2/2] platform/x86: dell-ddv: Fix temperature scaling

[Armin Wolf]

After using the built-in UEFI hardware diagnostics to compare
the measured battery temperature, i noticed that the temperature
is actually expressed in tenth degree kelvin, similar to the
SBS-Data standard. For example, a value of 2992 is displayed as
26 degrees celsius.
Fix the scaling so that the correct values are being displayed.

Tested on a Dell Inspiron 3505.

Fixes: a77272c16041 ("platform/x86: dell: Add new dell-wmi-ddv driver")
Signed-off-by: Armin Wolf <W_Armin@gmx.de>
---
Changes in v2:
- Avoid unnecessary rounding
---
 drivers/platform/x86/dell/dell-wmi-ddv.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/platform/x86/dell/dell-wmi-ddv.c b/drivers/platform/x86/dell/dell-wmi-ddv.c
index eff4e9649faf..2750dee99c3e 100644
--- a/drivers/platform/x86/dell/dell-wmi-ddv.c
+++ b/drivers/platform/x86/dell/dell-wmi-ddv.c
@@ -17,7 +17,6 @@
 #include <linux/kernel.h>
 #include <linux/hwmon.h>
 #include <linux/kstrtox.h>
-#include <linux/math.h>
 #include <linux/math64.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
@@ -665,7 +664,8 @@ static ssize_t temp_show(struct device *dev, struct device_attribute *attr, char
 	if (ret < 0)
 		return ret;

-	return sysfs_emit(buf, "%d\n", DIV_ROUND_CLOSEST(value, 10));
+	/* Use 2731 instead of 2731.5 to avoid unnecessary rounding */
+	return sysfs_emit(buf, "%d\n", value - 2731);
 }

 static ssize_t eppid_show(struct device *dev, struct device_attribute *attr, char *buf)
--
2.30.2

Re: [PATCH v2 1/2] platform/x86: dell-ddv: Fix cache invalidation on resume

[Armin Wolf]

Am 18.02.23 um 12:53 schrieb Armin Wolf:

> If one or both sensor buffers could not be initialized, either
> due to missing hardware support or due to some error during probing,
> the resume handler will encounter undefined behaviour when
> attempting to lock buffers then protected by an uninitialized or
> destroyed mutex.
> Fix this by introducing a "active" flag which is set during probe,
> and only invalidate buffers which where flaged as "active".
>
> Tested on a Dell Inspiron 3505.

Hello,

what is the status of this series? Both patches are tested on real hardware
and work flawlessly.

Armin Wolf

> Fixes: 3b7eeff93d29 ("platform/x86: dell-ddv: Add hwmon support")
> Signed-off-by: Armin Wolf <W_Armin@gmx.de>
> ---
> Changes in v2:
> - move checking of the "active" flag inside
>    dell_wmi_ddv_hwmon_cache_invalidate()
> ---
>   drivers/platform/x86/dell/dell-wmi-ddv.c | 8 +++++++-
>   1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/platform/x86/dell/dell-wmi-ddv.c b/drivers/platform/x86/dell/dell-wmi-ddv.c
> index d547c9d09725..eff4e9649faf 100644
> --- a/drivers/platform/x86/dell/dell-wmi-ddv.c
> +++ b/drivers/platform/x86/dell/dell-wmi-ddv.c
> @@ -96,6 +96,7 @@ struct combined_chip_info {
>   };
>
>   struct dell_wmi_ddv_sensors {
> +	bool active;
>   	struct mutex lock;	/* protect caching */
>   	unsigned long timestamp;
>   	union acpi_object *obj;
> @@ -520,6 +521,9 @@ static struct hwmon_channel_info *dell_wmi_ddv_channel_create(struct device *dev
>
>   static void dell_wmi_ddv_hwmon_cache_invalidate(struct dell_wmi_ddv_sensors *sensors)
>   {
> +	if (!sensors->active)
> +		return;
> +
>   	mutex_lock(&sensors->lock);
>   	kfree(sensors->obj);
>   	sensors->obj = NULL;
> @@ -530,6 +534,7 @@ static void dell_wmi_ddv_hwmon_cache_destroy(void *data)
>   {
>   	struct dell_wmi_ddv_sensors *sensors = data;
>
> +	sensors->active = false;
>   	mutex_destroy(&sensors->lock);
>   	kfree(sensors->obj);
>   }
> @@ -549,6 +554,7 @@ static struct hwmon_channel_info *dell_wmi_ddv_channel_init(struct wmi_device *w
>   		return ERR_PTR(ret);
>
>   	mutex_init(&sensors->lock);
> +	sensors->active = true;
>
>   	ret = devm_add_action_or_reset(&wdev->dev, dell_wmi_ddv_hwmon_cache_destroy, sensors);
>   	if (ret < 0)
> @@ -852,7 +858,7 @@ static int dell_wmi_ddv_resume(struct device *dev)
>   {
>   	struct dell_wmi_ddv_data *data = dev_get_drvdata(dev);
>
> -	/* Force re-reading of all sensors */
> +	/* Force re-reading of all active sensors */
>   	dell_wmi_ddv_hwmon_cache_invalidate(&data->fans);
>   	dell_wmi_ddv_hwmon_cache_invalidate(&data->temps);
>
> --
> 2.30.2
>

Re: [PATCH v2 1/2] platform/x86: dell-ddv: Fix cache invalidation on resume

[Hans de Goede]

Hi,

On 2/18/23 12:53, Armin Wolf wrote:
> If one or both sensor buffers could not be initialized, either
> due to missing hardware support or due to some error during probing,
> the resume handler will encounter undefined behaviour when
> attempting to lock buffers then protected by an uninitialized or
> destroyed mutex.
> Fix this by introducing a "active" flag which is set during probe,
> and only invalidate buffers which where flaged as "active".
> 
> Tested on a Dell Inspiron 3505.
> 
> Fixes: 3b7eeff93d29 ("platform/x86: dell-ddv: Add hwmon support")
> Signed-off-by: Armin Wolf <W_Armin@gmx.de>
> ---
> Changes in v2:
> - move checking of the "active" flag inside
>   dell_wmi_ddv_hwmon_cache_invalidate()

Thanks, I've applied this patch to my review-hans branch:
https://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86.git/log/?h=review-hans

I'll rebase that branch once 6.3-rc1 is out and then push the rebased
patch to the fixes branch and include it in my next 6.3 fixes pull-req
to Linus.

Regards,

Hans




> ---
>  drivers/platform/x86/dell/dell-wmi-ddv.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/platform/x86/dell/dell-wmi-ddv.c b/drivers/platform/x86/dell/dell-wmi-ddv.c
> index d547c9d09725..eff4e9649faf 100644
> --- a/drivers/platform/x86/dell/dell-wmi-ddv.c
> +++ b/drivers/platform/x86/dell/dell-wmi-ddv.c
> @@ -96,6 +96,7 @@ struct combined_chip_info {
>  };
> 
>  struct dell_wmi_ddv_sensors {
> +	bool active;
>  	struct mutex lock;	/* protect caching */
>  	unsigned long timestamp;
>  	union acpi_object *obj;
> @@ -520,6 +521,9 @@ static struct hwmon_channel_info *dell_wmi_ddv_channel_create(struct device *dev
> 
>  static void dell_wmi_ddv_hwmon_cache_invalidate(struct dell_wmi_ddv_sensors *sensors)
>  {
> +	if (!sensors->active)
> +		return;
> +
>  	mutex_lock(&sensors->lock);
>  	kfree(sensors->obj);
>  	sensors->obj = NULL;
> @@ -530,6 +534,7 @@ static void dell_wmi_ddv_hwmon_cache_destroy(void *data)
>  {
>  	struct dell_wmi_ddv_sensors *sensors = data;
> 
> +	sensors->active = false;
>  	mutex_destroy(&sensors->lock);
>  	kfree(sensors->obj);
>  }
> @@ -549,6 +554,7 @@ static struct hwmon_channel_info *dell_wmi_ddv_channel_init(struct wmi_device *w
>  		return ERR_PTR(ret);
> 
>  	mutex_init(&sensors->lock);
> +	sensors->active = true;
> 
>  	ret = devm_add_action_or_reset(&wdev->dev, dell_wmi_ddv_hwmon_cache_destroy, sensors);
>  	if (ret < 0)
> @@ -852,7 +858,7 @@ static int dell_wmi_ddv_resume(struct device *dev)
>  {
>  	struct dell_wmi_ddv_data *data = dev_get_drvdata(dev);
> 
> -	/* Force re-reading of all sensors */
> +	/* Force re-reading of all active sensors */
>  	dell_wmi_ddv_hwmon_cache_invalidate(&data->fans);
>  	dell_wmi_ddv_hwmon_cache_invalidate(&data->temps);
> 
> --
> 2.30.2
> 

Re: [PATCH v2 2/2] platform/x86: dell-ddv: Fix temperature scaling

[Hans de Goede]

Hi,

On 2/18/23 12:53, Armin Wolf wrote:
> After using the built-in UEFI hardware diagnostics to compare
> the measured battery temperature, i noticed that the temperature
> is actually expressed in tenth degree kelvin, similar to the
> SBS-Data standard. For example, a value of 2992 is displayed as
> 26 degrees celsius.
> Fix the scaling so that the correct values are being displayed.
> 
> Tested on a Dell Inspiron 3505.
> 
> Fixes: a77272c16041 ("platform/x86: dell: Add new dell-wmi-ddv driver")
> Signed-off-by: Armin Wolf <W_Armin@gmx.de>

Thanks, I've applied this patch to my review-hans branch:
https://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86.git/log/?h=review-hans

I'll rebase that branch once 6.3-rc1 is out and then push the rebased
patch to the fixes branch and include it in my next 6.3 fixes pull-req
to Linus.

Regards,

Hans



> ---
> Changes in v2:
> - Avoid unnecessary rounding
> ---
>  drivers/platform/x86/dell/dell-wmi-ddv.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/platform/x86/dell/dell-wmi-ddv.c b/drivers/platform/x86/dell/dell-wmi-ddv.c
> index eff4e9649faf..2750dee99c3e 100644
> --- a/drivers/platform/x86/dell/dell-wmi-ddv.c
> +++ b/drivers/platform/x86/dell/dell-wmi-ddv.c
> @@ -17,7 +17,6 @@
>  #include <linux/kernel.h>
>  #include <linux/hwmon.h>
>  #include <linux/kstrtox.h>
> -#include <linux/math.h>
>  #include <linux/math64.h>
>  #include <linux/module.h>
>  #include <linux/mutex.h>
> @@ -665,7 +664,8 @@ static ssize_t temp_show(struct device *dev, struct device_attribute *attr, char
>  	if (ret < 0)
>  		return ret;
> 
> -	return sysfs_emit(buf, "%d\n", DIV_ROUND_CLOSEST(value, 10));
> +	/* Use 2731 instead of 2731.5 to avoid unnecessary rounding */
> +	return sysfs_emit(buf, "%d\n", value - 2731);
>  }
> 
>  static ssize_t eppid_show(struct device *dev, struct device_attribute *attr, char *buf)
> --
> 2.30.2
>