[PATCH 1/5] pipeline_handler: Fix unlocking media devices too early when there are multiple cameras

[Hans de Goede]

Hi,

On 8/20/24 9:50 PM, Hans de Goede wrote:
> PipelineHandler::acquire() only locks the media devices when the first
> camera is acquired. If a second camera of a pipeline is acquired only
> useCount_ is increased and nothing else is done.
> 
> When releasing cameras PipelineHandler::release() should only unlock
> the media devices when the last camera is released. But the old code
> unlocked on every release().
> 
> Fix PipelineHandler::release() to only release the media devices when
> the last camera is released.
> 
> Signed-off-by: Hans de Goede <hdegoede at redhat.com>

Note this is a resend of the standalone fix which I send out earlier
since the rest of the series depends on this.

The standalone posting already has a:

Reviewed-by: Harvey Yang <chenghaoyang at chromium.org>

which I forgot to add here.

Regards,

Hans


> ---
>  src/libcamera/pipeline_handler.cpp | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/src/libcamera/pipeline_handler.cpp b/src/libcamera/pipeline_handler.cpp
> index 5a6de685..a20cd27d 100644
> --- a/src/libcamera/pipeline_handler.cpp
> +++ b/src/libcamera/pipeline_handler.cpp
> @@ -205,7 +205,8 @@ void PipelineHandler::release(Camera *camera)
>  
>  	ASSERT(useCount_);
>  
> -	unlockMediaDevices();
> +	if (useCount_ == 1)
> +		unlockMediaDevices();
>  
>  	releaseDevice(camera);
>