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

[PATCH 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 | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
index 4c6198c48dd6..acb7c3003ab6 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) {
@@ -431,6 +422,16 @@ static int call_s_stream(struct v4l2_subdev *sd, int enable)
 	if (!ret)
 		sd->enabled_streams = enable ? BIT(0) : 0;
 
+#if IS_REACHABLE(CONFIG_LEDS_CLASS)
+	if (!IS_ERR_OR_NULL(sd->privacy_led) && !(enable && ret < 0)) {
+		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 1/1] media: v4l: Don't turn on privacy LED if streamon fails

[Hans de Goede]

Hi Sakari,

Thank you for fixing this.

On 4/10/24 12:03 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>
> ---
>  drivers/media/v4l2-core/v4l2-subdev.c | 19 ++++++++++---------
>  1 file changed, 10 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
> index 4c6198c48dd6..acb7c3003ab6 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) {
> @@ -431,6 +422,16 @@ static int call_s_stream(struct v4l2_subdev *sd, int enable)
>  	if (!ret)
>  		sd->enabled_streams = enable ? BIT(0) : 0;
>  
> +#if IS_REACHABLE(CONFIG_LEDS_CLASS)
> +	if (!IS_ERR_OR_NULL(sd->privacy_led) && !(enable && ret < 0)) {

There already is a:

	if (!enable && ret < 0)
		ret = 0;

block above to ignore stream-off errors, so you can just test for:

	if (!ret && !IS_ERR_OR_NULL(sd->privacy_led)) {
		...
	}

And then you can move the whole block to inside the existing:

	if (!ret)
		sd->enabled_streams = enable ? BIT(0) : 0;

block, so you get something like this:

	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
	}

Which then cleans up nicely by Tomi's patch
introducing the privacy LED helper functions,
to something like this:

	if (!ret {
		if (enable) {
			sd->enabled_streams = BIT(0);
			v4l2_subdev_enable_privacy_led(sd);
		} else {
			sd->enabled_streams = 0;
			v4l2_subdev_disable_privacy_led(sd);
		}
	}

Regards,

Hans

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

[Sakari Ailus]

Hi Hans,

Thanks for the review.

On Wed, Apr 10, 2024 at 12:12:33PM +0200, Hans de Goede wrote:
> Hi Sakari,
> 
> Thank you for fixing this.
> 
> On 4/10/24 12:03 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>
> > ---
> >  drivers/media/v4l2-core/v4l2-subdev.c | 19 ++++++++++---------
> >  1 file changed, 10 insertions(+), 9 deletions(-)
> > 
> > diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
> > index 4c6198c48dd6..acb7c3003ab6 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) {
> > @@ -431,6 +422,16 @@ static int call_s_stream(struct v4l2_subdev *sd, int enable)
> >  	if (!ret)
> >  		sd->enabled_streams = enable ? BIT(0) : 0;
> >  
> > +#if IS_REACHABLE(CONFIG_LEDS_CLASS)
> > +	if (!IS_ERR_OR_NULL(sd->privacy_led) && !(enable && ret < 0)) {
> 
> There already is a:
> 
> 	if (!enable && ret < 0)
> 		ret = 0;
> 
> block above to ignore stream-off errors, so you can just test for:
> 
> 	if (!ret && !IS_ERR_OR_NULL(sd->privacy_led)) {
> 		...
> 	}
> 
> And then you can move the whole block to inside the existing:
> 
> 	if (!ret)
> 		sd->enabled_streams = enable ? BIT(0) : 0;
> 
> block, so you get something like this:
> 
> 	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
> 	}

Seems reasonable, I'll send v2.

> 
> Which then cleans up nicely by Tomi's patch
> introducing the privacy LED helper functions,
> to something like this:
> 
> 	if (!ret {
> 		if (enable) {
> 			sd->enabled_streams = BIT(0);
> 			v4l2_subdev_enable_privacy_led(sd);
> 		} else {
> 			sd->enabled_streams = 0;
> 			v4l2_subdev_disable_privacy_led(sd);
> 		}
> 	}
> 

-- 
Kind regards,

Sakari Ailus

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

[Sakari Ailus]

On Wed, Apr 10, 2024 at 11:31:48AM +0000, Sakari Ailus wrote:
> Hi Hans,
> 
> Thanks for the review.
> 
> On Wed, Apr 10, 2024 at 12:12:33PM +0200, Hans de Goede wrote:
> > Hi Sakari,
> > 
> > Thank you for fixing this.
> > 
> > On 4/10/24 12:03 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>
> > > ---
> > >  drivers/media/v4l2-core/v4l2-subdev.c | 19 ++++++++++---------
> > >  1 file changed, 10 insertions(+), 9 deletions(-)
> > > 
> > > diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
> > > index 4c6198c48dd6..acb7c3003ab6 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) {
> > > @@ -431,6 +422,16 @@ static int call_s_stream(struct v4l2_subdev *sd, int enable)
> > >  	if (!ret)
> > >  		sd->enabled_streams = enable ? BIT(0) : 0;
> > >  
> > > +#if IS_REACHABLE(CONFIG_LEDS_CLASS)
> > > +	if (!IS_ERR_OR_NULL(sd->privacy_led) && !(enable && ret < 0)) {
> > 
> > There already is a:
> > 
> > 	if (!enable && ret < 0)
> > 		ret = 0;
> > 
> > block above to ignore stream-off errors, so you can just test for:
> > 
> > 	if (!ret && !IS_ERR_OR_NULL(sd->privacy_led)) {
> > 		...
> > 	}
> > 
> > And then you can move the whole block to inside the existing:
> > 
> > 	if (!ret)
> > 		sd->enabled_streams = enable ? BIT(0) : 0;
> > 
> > block, so you get something like this:
> > 
> > 	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
> > 	}
> 
> Seems reasonable, I'll send v2.

I was a bit too fast to hit y. ret will be non-zero if streamon fails
(enable non-zero), in which case the LED needs to be turned off. So you
can't have !ret condition for all LED control.

> 
> > 
> > Which then cleans up nicely by Tomi's patch
> > introducing the privacy LED helper functions,
> > to something like this:
> > 
> > 	if (!ret {
> > 		if (enable) {
> > 			sd->enabled_streams = BIT(0);
> > 			v4l2_subdev_enable_privacy_led(sd);
> > 		} else {
> > 			sd->enabled_streams = 0;
> > 			v4l2_subdev_disable_privacy_led(sd);
> > 		}
> > 	}
> > 
> 

-- 
Sakari Ailus

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

[Hans de Goede]

Hi,

On 4/10/24 1:35 PM, Sakari Ailus wrote:
> On Wed, Apr 10, 2024 at 11:31:48AM +0000, Sakari Ailus wrote:
>> Hi Hans,
>>
>> Thanks for the review.
>>
>> On Wed, Apr 10, 2024 at 12:12:33PM +0200, Hans de Goede wrote:
>>> Hi Sakari,
>>>
>>> Thank you for fixing this.
>>>
>>> On 4/10/24 12:03 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>
>>>> ---
>>>>  drivers/media/v4l2-core/v4l2-subdev.c | 19 ++++++++++---------
>>>>  1 file changed, 10 insertions(+), 9 deletions(-)
>>>>
>>>> diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
>>>> index 4c6198c48dd6..acb7c3003ab6 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) {
>>>> @@ -431,6 +422,16 @@ static int call_s_stream(struct v4l2_subdev *sd, int enable)
>>>>  	if (!ret)
>>>>  		sd->enabled_streams = enable ? BIT(0) : 0;
>>>>  
>>>> +#if IS_REACHABLE(CONFIG_LEDS_CLASS)
>>>> +	if (!IS_ERR_OR_NULL(sd->privacy_led) && !(enable && ret < 0)) {
>>>
>>> There already is a:
>>>
>>> 	if (!enable && ret < 0)
>>> 		ret = 0;
>>>
>>> block above to ignore stream-off errors, so you can just test for:
>>>
>>> 	if (!ret && !IS_ERR_OR_NULL(sd->privacy_led)) {
>>> 		...
>>> 	}
>>>
>>> And then you can move the whole block to inside the existing:
>>>
>>> 	if (!ret)
>>> 		sd->enabled_streams = enable ? BIT(0) : 0;
>>>
>>> block, so you get something like this:
>>>
>>> 	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
>>> 	}
>>
>> Seems reasonable, I'll send v2.
> 
> I was a bit too fast to hit y. ret will be non-zero if streamon fails
> (enable non-zero), in which case the LED needs to be turned off. So you
> can't have !ret condition for all LED control.

But if stream-on fails then AFAICT the LED was never turned on in the first
place. stream on / off calls must always be balanced, right ?

IOW stream-on is not supposed to get called if the device is already
streaming and if the device is not already streaming then the LED will
already be off.

Regards,

Hans



> 
>>
>>>
>>> Which then cleans up nicely by Tomi's patch
>>> introducing the privacy LED helper functions,
>>> to something like this:
>>>
>>> 	if (!ret {
>>> 		if (enable) {
>>> 			sd->enabled_streams = BIT(0);
>>> 			v4l2_subdev_enable_privacy_led(sd);
>>> 		} else {
>>> 			sd->enabled_streams = 0;
>>> 			v4l2_subdev_disable_privacy_led(sd);
>>> 		}
>>> 	}
>>>
>>
> 

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

[Sakari Ailus]

On Wed, Apr 10, 2024 at 01:37:13PM +0200, Hans de Goede wrote:
> Hi,
> 
> On 4/10/24 1:35 PM, Sakari Ailus wrote:
> > On Wed, Apr 10, 2024 at 11:31:48AM +0000, Sakari Ailus wrote:
> >> Hi Hans,
> >>
> >> Thanks for the review.
> >>
> >> On Wed, Apr 10, 2024 at 12:12:33PM +0200, Hans de Goede wrote:
> >>> Hi Sakari,
> >>>
> >>> Thank you for fixing this.
> >>>
> >>> On 4/10/24 12:03 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>
> >>>> ---
> >>>>  drivers/media/v4l2-core/v4l2-subdev.c | 19 ++++++++++---------
> >>>>  1 file changed, 10 insertions(+), 9 deletions(-)
> >>>>
> >>>> diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
> >>>> index 4c6198c48dd6..acb7c3003ab6 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) {
> >>>> @@ -431,6 +422,16 @@ static int call_s_stream(struct v4l2_subdev *sd, int enable)
> >>>>  	if (!ret)
> >>>>  		sd->enabled_streams = enable ? BIT(0) : 0;
> >>>>  
> >>>> +#if IS_REACHABLE(CONFIG_LEDS_CLASS)
> >>>> +	if (!IS_ERR_OR_NULL(sd->privacy_led) && !(enable && ret < 0)) {
> >>>
> >>> There already is a:
> >>>
> >>> 	if (!enable && ret < 0)
> >>> 		ret = 0;
> >>>
> >>> block above to ignore stream-off errors, so you can just test for:
> >>>
> >>> 	if (!ret && !IS_ERR_OR_NULL(sd->privacy_led)) {
> >>> 		...
> >>> 	}
> >>>
> >>> And then you can move the whole block to inside the existing:
> >>>
> >>> 	if (!ret)
> >>> 		sd->enabled_streams = enable ? BIT(0) : 0;
> >>>
> >>> block, so you get something like this:
> >>>
> >>> 	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
> >>> 	}
> >>
> >> Seems reasonable, I'll send v2.
> > 
> > I was a bit too fast to hit y. ret will be non-zero if streamon fails
> > (enable non-zero), in which case the LED needs to be turned off. So you
> > can't have !ret condition for all LED control.
> 
> But if stream-on fails then AFAICT the LED was never turned on in the first
> place. stream on / off calls must always be balanced, right ?
> 
> IOW stream-on is not supposed to get called if the device is already
> streaming and if the device is not already streaming then the LED will
> already be off.

Ah, right. I missed that part. I'll send v2 after all. :-)

-- 
Sakari Ailus