[PATCH v2 1/1] media: v4l: Don't turn on privacy LED if streamon fails

[PATCH v2 1/1] media: v4l: Don't turn on privacy LED if streamon fails

[Sakari Ailus]

Turn on the privacy LED only if streamon succeeds. This can be done after
enabling streaming on the sensor.

Fixes: b6e10ff6c23d ("media: v4l2-core: Make the v4l2-core code enable/disable the privacy LED if present")
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
 drivers/media/v4l2-core/v4l2-subdev.c | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
index 4c6198c48dd6..012b757eac9f 100644
--- a/drivers/media/v4l2-core/v4l2-subdev.c
+++ b/drivers/media/v4l2-core/v4l2-subdev.c
@@ -412,15 +412,6 @@ static int call_s_stream(struct v4l2_subdev *sd, int enable)
 	if (WARN_ON(!!sd->enabled_streams == !!enable))
 		return 0;
 
-#if IS_REACHABLE(CONFIG_LEDS_CLASS)
-	if (!IS_ERR_OR_NULL(sd->privacy_led)) {
-		if (enable)
-			led_set_brightness(sd->privacy_led,
-					   sd->privacy_led->max_brightness);
-		else
-			led_set_brightness(sd->privacy_led, 0);
-	}
-#endif
 	ret = sd->ops->video->s_stream(sd, enable);
 
 	if (!enable && ret < 0) {
@@ -428,9 +419,20 @@ static int call_s_stream(struct v4l2_subdev *sd, int enable)
 		ret = 0;
 	}
 
-	if (!ret)
+	if (!ret) {
 		sd->enabled_streams = enable ? BIT(0) : 0;
 
+#if IS_REACHABLE(CONFIG_LEDS_CLASS)
+		if (!IS_ERR_OR_NULL(sd->privacy_led)) {
+			if (enable)
+				led_set_brightness(sd->privacy_led,
+						   sd->privacy_led->max_brightness);
+			else
+				led_set_brightness(sd->privacy_led, 0);
+		}
+#endif
+	}
+
 	return ret;
 }
 
-- 
2.39.2

Re: [PATCH v2 1/1] media: v4l: Don't turn on privacy LED if streamon fails

[Hans de Goede]

Hi,

On 4/10/24 1:47 PM, Sakari Ailus wrote:
> Turn on the privacy LED only if streamon succeeds. This can be done after
> enabling streaming on the sensor.
> 
> Fixes: b6e10ff6c23d ("media: v4l2-core: Make the v4l2-core code enable/disable the privacy LED if present")
> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>

Thanks, patch looks good to me:

Reviewed-by: Hans de Goede <hdegoede@redhat.com>

Regards,

Hans



> ---
>  drivers/media/v4l2-core/v4l2-subdev.c | 22 ++++++++++++----------
>  1 file changed, 12 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
> index 4c6198c48dd6..012b757eac9f 100644
> --- a/drivers/media/v4l2-core/v4l2-subdev.c
> +++ b/drivers/media/v4l2-core/v4l2-subdev.c
> @@ -412,15 +412,6 @@ static int call_s_stream(struct v4l2_subdev *sd, int enable)
>  	if (WARN_ON(!!sd->enabled_streams == !!enable))
>  		return 0;
>  
> -#if IS_REACHABLE(CONFIG_LEDS_CLASS)
> -	if (!IS_ERR_OR_NULL(sd->privacy_led)) {
> -		if (enable)
> -			led_set_brightness(sd->privacy_led,
> -					   sd->privacy_led->max_brightness);
> -		else
> -			led_set_brightness(sd->privacy_led, 0);
> -	}
> -#endif
>  	ret = sd->ops->video->s_stream(sd, enable);
>  
>  	if (!enable && ret < 0) {
> @@ -428,9 +419,20 @@ static int call_s_stream(struct v4l2_subdev *sd, int enable)
>  		ret = 0;
>  	}
>  
> -	if (!ret)
> +	if (!ret) {
>  		sd->enabled_streams = enable ? BIT(0) : 0;
>  
> +#if IS_REACHABLE(CONFIG_LEDS_CLASS)
> +		if (!IS_ERR_OR_NULL(sd->privacy_led)) {
> +			if (enable)
> +				led_set_brightness(sd->privacy_led,
> +						   sd->privacy_led->max_brightness);
> +			else
> +				led_set_brightness(sd->privacy_led, 0);
> +		}
> +#endif
> +	}
> +
>  	return ret;
>  }
>  

Re: [PATCH v2 1/1] media: v4l: Don't turn on privacy LED if streamon fails

[Tomi Valkeinen]

On 10/04/2024 14:47, Sakari Ailus wrote:
> Turn on the privacy LED only if streamon succeeds. This can be done after
> enabling streaming on the sensor.
> 
> Fixes: b6e10ff6c23d ("media: v4l2-core: Make the v4l2-core code enable/disable the privacy LED if present")
> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> ---
>   drivers/media/v4l2-core/v4l2-subdev.c | 22 ++++++++++++----------
>   1 file changed, 12 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
> index 4c6198c48dd6..012b757eac9f 100644
> --- a/drivers/media/v4l2-core/v4l2-subdev.c
> +++ b/drivers/media/v4l2-core/v4l2-subdev.c
> @@ -412,15 +412,6 @@ static int call_s_stream(struct v4l2_subdev *sd, int enable)
>   	if (WARN_ON(!!sd->enabled_streams == !!enable))
>   		return 0;
>   
> -#if IS_REACHABLE(CONFIG_LEDS_CLASS)
> -	if (!IS_ERR_OR_NULL(sd->privacy_led)) {
> -		if (enable)
> -			led_set_brightness(sd->privacy_led,
> -					   sd->privacy_led->max_brightness);
> -		else
> -			led_set_brightness(sd->privacy_led, 0);
> -	}
> -#endif
>   	ret = sd->ops->video->s_stream(sd, enable);
>   
>   	if (!enable && ret < 0) {
> @@ -428,9 +419,20 @@ static int call_s_stream(struct v4l2_subdev *sd, int enable)
>   		ret = 0;
>   	}
>   
> -	if (!ret)
> +	if (!ret) {
>   		sd->enabled_streams = enable ? BIT(0) : 0;
>   
> +#if IS_REACHABLE(CONFIG_LEDS_CLASS)
> +		if (!IS_ERR_OR_NULL(sd->privacy_led)) {
> +			if (enable)
> +				led_set_brightness(sd->privacy_led,
> +						   sd->privacy_led->max_brightness);
> +			else
> +				led_set_brightness(sd->privacy_led, 0);
> +		}
> +#endif
> +	}
> +
>   	return ret;
>   }
>   

Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>

  Tomi

Re: [PATCH v2 1/1] media: v4l: Don't turn on privacy LED if streamon fails

[Umang Jain]

Hi Sakari,

Thank you for the patch

On 10/04/24 5:18 pm, Hans de Goede wrote:
> Hi,
>
> On 4/10/24 1:47 PM, Sakari Ailus wrote:
>> Turn on the privacy LED only if streamon succeeds. This can be done after
>> enabling streaming on the sensor.
>>
>> Fixes: b6e10ff6c23d ("media: v4l2-core: Make the v4l2-core code enable/disable the privacy LED if present")
>> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> Thanks, patch looks good to me:

Looks good to me too
>
> Reviewed-by: Hans de Goede <hdegoede@redhat.com>

Reviewed-by: Umang Jain <umang.jain@ideasonboard.com>

>
> Regards,
>
> Hans
>
>
>
>> ---
>>   drivers/media/v4l2-core/v4l2-subdev.c | 22 ++++++++++++----------
>>   1 file changed, 12 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
>> index 4c6198c48dd6..012b757eac9f 100644
>> --- a/drivers/media/v4l2-core/v4l2-subdev.c
>> +++ b/drivers/media/v4l2-core/v4l2-subdev.c
>> @@ -412,15 +412,6 @@ static int call_s_stream(struct v4l2_subdev *sd, int enable)
>>   	if (WARN_ON(!!sd->enabled_streams == !!enable))
>>   		return 0;
>>   
>> -#if IS_REACHABLE(CONFIG_LEDS_CLASS)
>> -	if (!IS_ERR_OR_NULL(sd->privacy_led)) {
>> -		if (enable)
>> -			led_set_brightness(sd->privacy_led,
>> -					   sd->privacy_led->max_brightness);
>> -		else
>> -			led_set_brightness(sd->privacy_led, 0);
>> -	}
>> -#endif
>>   	ret = sd->ops->video->s_stream(sd, enable);
>>   
>>   	if (!enable && ret < 0) {
>> @@ -428,9 +419,20 @@ static int call_s_stream(struct v4l2_subdev *sd, int enable)
>>   		ret = 0;
>>   	}
>>   
>> -	if (!ret)
>> +	if (!ret) {
>>   		sd->enabled_streams = enable ? BIT(0) : 0;
>>   
>> +#if IS_REACHABLE(CONFIG_LEDS_CLASS)
>> +		if (!IS_ERR_OR_NULL(sd->privacy_led)) {
>> +			if (enable)
>> +				led_set_brightness(sd->privacy_led,
>> +						   sd->privacy_led->max_brightness);
>> +			else
>> +				led_set_brightness(sd->privacy_led, 0);
>> +		}
>> +#endif
>> +	}
>> +
>>   	return ret;
>>   }
>>   

Re: [PATCH v2 1/1] media: v4l: Don't turn on privacy LED if streamon fails

[Laurent Pinchart]

Hi Sakari,

Thank you for the patch.

On Wed, Apr 10, 2024 at 02:47:12PM +0300, Sakari Ailus wrote:
> Turn on the privacy LED only if streamon succeeds. This can be done after
> enabling streaming on the sensor.
> 
> Fixes: b6e10ff6c23d ("media: v4l2-core: Make the v4l2-core code enable/disable the privacy LED if present")
> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> ---
>  drivers/media/v4l2-core/v4l2-subdev.c | 22 ++++++++++++----------
>  1 file changed, 12 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
> index 4c6198c48dd6..012b757eac9f 100644
> --- a/drivers/media/v4l2-core/v4l2-subdev.c
> +++ b/drivers/media/v4l2-core/v4l2-subdev.c
> @@ -412,15 +412,6 @@ static int call_s_stream(struct v4l2_subdev *sd, int enable)
>  	if (WARN_ON(!!sd->enabled_streams == !!enable))
>  		return 0;
>  
> -#if IS_REACHABLE(CONFIG_LEDS_CLASS)
> -	if (!IS_ERR_OR_NULL(sd->privacy_led)) {
> -		if (enable)
> -			led_set_brightness(sd->privacy_led,
> -					   sd->privacy_led->max_brightness);
> -		else
> -			led_set_brightness(sd->privacy_led, 0);
> -	}
> -#endif
>  	ret = sd->ops->video->s_stream(sd, enable);
>  
>  	if (!enable && ret < 0) {
> @@ -428,9 +419,20 @@ static int call_s_stream(struct v4l2_subdev *sd, int enable)
>  		ret = 0;
>  	}
>  
> -	if (!ret)
> +	if (!ret) {
>  		sd->enabled_streams = enable ? BIT(0) : 0;
>  
> +#if IS_REACHABLE(CONFIG_LEDS_CLASS)
> +		if (!IS_ERR_OR_NULL(sd->privacy_led)) {
> +			if (enable)
> +				led_set_brightness(sd->privacy_led,
> +						   sd->privacy_led->max_brightness);
> +			else
> +				led_set_brightness(sd->privacy_led, 0);
> +		}
> +#endif

This means that the LED will be turned slightly after the camera is
enabled. I don't think it's an issue in practice. Another possibly more
important concern is that we should maybe check the return value of
led_set_brightness(), and fail .s_stream() when we can't enable the
privacy LED at stream on time. In that case, it would be best to keep
turning the privacy LED on before calling .s_stream(). It should still
be turned off only after calling .s_stream() though.

> +	}
> +
>  	return ret;
>  }
>  

-- 
Regards,

Laurent Pinchart

Re: [PATCH v2 1/1] media: v4l: Don't turn on privacy LED if streamon fails

[Sakari Ailus]

Hi Laurent,

On Fri, Apr 12, 2024 at 08:46:21PM +0300, Laurent Pinchart wrote:
> Hi Sakari,
> 
> Thank you for the patch.
> 
> On Wed, Apr 10, 2024 at 02:47:12PM +0300, Sakari Ailus wrote:
> > Turn on the privacy LED only if streamon succeeds. This can be done after
> > enabling streaming on the sensor.
> > 
> > Fixes: b6e10ff6c23d ("media: v4l2-core: Make the v4l2-core code enable/disable the privacy LED if present")
> > Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> > ---
> >  drivers/media/v4l2-core/v4l2-subdev.c | 22 ++++++++++++----------
> >  1 file changed, 12 insertions(+), 10 deletions(-)
> > 
> > diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
> > index 4c6198c48dd6..012b757eac9f 100644
> > --- a/drivers/media/v4l2-core/v4l2-subdev.c
> > +++ b/drivers/media/v4l2-core/v4l2-subdev.c
> > @@ -412,15 +412,6 @@ static int call_s_stream(struct v4l2_subdev *sd, int enable)
> >  	if (WARN_ON(!!sd->enabled_streams == !!enable))
> >  		return 0;
> >  
> > -#if IS_REACHABLE(CONFIG_LEDS_CLASS)
> > -	if (!IS_ERR_OR_NULL(sd->privacy_led)) {
> > -		if (enable)
> > -			led_set_brightness(sd->privacy_led,
> > -					   sd->privacy_led->max_brightness);
> > -		else
> > -			led_set_brightness(sd->privacy_led, 0);
> > -	}
> > -#endif
> >  	ret = sd->ops->video->s_stream(sd, enable);
> >  
> >  	if (!enable && ret < 0) {
> > @@ -428,9 +419,20 @@ static int call_s_stream(struct v4l2_subdev *sd, int enable)
> >  		ret = 0;
> >  	}
> >  
> > -	if (!ret)
> > +	if (!ret) {
> >  		sd->enabled_streams = enable ? BIT(0) : 0;
> >  
> > +#if IS_REACHABLE(CONFIG_LEDS_CLASS)
> > +		if (!IS_ERR_OR_NULL(sd->privacy_led)) {
> > +			if (enable)
> > +				led_set_brightness(sd->privacy_led,
> > +						   sd->privacy_led->max_brightness);
> > +			else
> > +				led_set_brightness(sd->privacy_led, 0);
> > +		}
> > +#endif
> 
> This means that the LED will be turned slightly after the camera is
> enabled. I don't think it's an issue in practice. Another possibly more

That's what I'd think as well. Typically even the exposure time is much,
much longer than what it takes to get here.

> important concern is that we should maybe check the return value of
> led_set_brightness(), and fail .s_stream() when we can't enable the
> privacy LED at stream on time. In that case, it would be best to keep
> turning the privacy LED on before calling .s_stream(). It should still
> be turned off only after calling .s_stream() though.

The return type of led_set_brightness() is void. Maybe because a large
majority is GPIO-controlled?

-- 
Regards,

Sakari Ailus

Re: [PATCH v2 1/1] media: v4l: Don't turn on privacy LED if streamon fails

[Laurent Pinchart]

On Mon, Apr 15, 2024 at 07:15:42AM +0000, Sakari Ailus wrote:
> Hi Laurent,
> 
> On Fri, Apr 12, 2024 at 08:46:21PM +0300, Laurent Pinchart wrote:
> > Hi Sakari,
> > 
> > Thank you for the patch.
> > 
> > On Wed, Apr 10, 2024 at 02:47:12PM +0300, Sakari Ailus wrote:
> > > Turn on the privacy LED only if streamon succeeds. This can be done after
> > > enabling streaming on the sensor.
> > > 
> > > Fixes: b6e10ff6c23d ("media: v4l2-core: Make the v4l2-core code enable/disable the privacy LED if present")
> > > Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> > > ---
> > >  drivers/media/v4l2-core/v4l2-subdev.c | 22 ++++++++++++----------
> > >  1 file changed, 12 insertions(+), 10 deletions(-)
> > > 
> > > diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
> > > index 4c6198c48dd6..012b757eac9f 100644
> > > --- a/drivers/media/v4l2-core/v4l2-subdev.c
> > > +++ b/drivers/media/v4l2-core/v4l2-subdev.c
> > > @@ -412,15 +412,6 @@ static int call_s_stream(struct v4l2_subdev *sd, int enable)
> > >  	if (WARN_ON(!!sd->enabled_streams == !!enable))
> > >  		return 0;
> > >  
> > > -#if IS_REACHABLE(CONFIG_LEDS_CLASS)
> > > -	if (!IS_ERR_OR_NULL(sd->privacy_led)) {
> > > -		if (enable)
> > > -			led_set_brightness(sd->privacy_led,
> > > -					   sd->privacy_led->max_brightness);
> > > -		else
> > > -			led_set_brightness(sd->privacy_led, 0);
> > > -	}
> > > -#endif
> > >  	ret = sd->ops->video->s_stream(sd, enable);
> > >  
> > >  	if (!enable && ret < 0) {
> > > @@ -428,9 +419,20 @@ static int call_s_stream(struct v4l2_subdev *sd, int enable)
> > >  		ret = 0;
> > >  	}
> > >  
> > > -	if (!ret)
> > > +	if (!ret) {
> > >  		sd->enabled_streams = enable ? BIT(0) : 0;
> > >  
> > > +#if IS_REACHABLE(CONFIG_LEDS_CLASS)
> > > +		if (!IS_ERR_OR_NULL(sd->privacy_led)) {
> > > +			if (enable)
> > > +				led_set_brightness(sd->privacy_led,
> > > +						   sd->privacy_led->max_brightness);
> > > +			else
> > > +				led_set_brightness(sd->privacy_led, 0);
> > > +		}
> > > +#endif
> > 
> > This means that the LED will be turned slightly after the camera is
> > enabled. I don't think it's an issue in practice. Another possibly more
> 
> That's what I'd think as well. Typically even the exposure time is much,
> much longer than what it takes to get here.
> 
> > important concern is that we should maybe check the return value of
> > led_set_brightness(), and fail .s_stream() when we can't enable the
> > privacy LED at stream on time. In that case, it would be best to keep
> > turning the privacy LED on before calling .s_stream(). It should still
> > be turned off only after calling .s_stream() though.
> 
> The return type of led_set_brightness() is void.

Oops :-S

> Maybe because a large majority is GPIO-controlled?

GPIOs can fail, in particular when they're on I2C GPIO expanders.

-- 
Regards,

Laurent Pinchart

Re: [PATCH v2 1/1] media: v4l: Don't turn on privacy LED if streamon fails

[Sakari Ailus]

On Mon, Apr 15, 2024 at 10:18:12AM +0300, Laurent Pinchart wrote:
> > Maybe because a large majority is GPIO-controlled?
> 
> GPIOs can fail, in particular when they're on I2C GPIO expanders.

Sure, but gpiod_set_value() return type is also void.

It just works... right?

-- 
Sakari Ailus

Re: [PATCH v2 1/1] media: v4l: Don't turn on privacy LED if streamon fails

[Laurent Pinchart]

On Mon, Apr 15, 2024 at 07:29:41AM +0000, Sakari Ailus wrote:
> On Mon, Apr 15, 2024 at 10:18:12AM +0300, Laurent Pinchart wrote:
> > > Maybe because a large majority is GPIO-controlled?
> > 
> > GPIOs can fail, in particular when they're on I2C GPIO expanders.
> 
> Sure, but gpiod_set_value() return type is also void.

I know, so there's nothing we can do short term.

> It just works... right?

Until it doesn't :-)

-- 
Regards,

Laurent Pinchart