Re: [PATCH] media: bcm2835-unicam: Fix log status runtime access

[Jean-Michel Hautbois]

Hi Eugen,

Thanks for the fix, the issue is real, but I think the patch leaks a 
runtime PM reference.

Le 21/05/2026 à 20:09, Eugen Hristev a écrit :
> When requesting log status, the block might be powered
> off, but registers are being read.
> Avoid reading the registers if the device is not
> resumed, thus also avoid powering up the device just
> for log status.
>
> Fixes: 392cd78d495f ("media: bcm2835-unicam: Add support for CCP2/CSI2 camera interface")
> Signed-off-by: Eugen Hristev <ehristev@xxxxxxxxxx>
> ---
>   drivers/media/platform/broadcom/bcm2835-unicam.c | 4 ++++
>   1 file changed, 4 insertions(+)
>
> diff --git a/drivers/media/platform/broadcom/bcm2835-unicam.c b/drivers/media/platform/broadcom/bcm2835-unicam.c
> index 8d28ba0b59a3..818694f007e2 100644
> --- a/drivers/media/platform/broadcom/bcm2835-unicam.c
> +++ b/drivers/media/platform/broadcom/bcm2835-unicam.c
> @@ -2052,6 +2052,10 @@ static int unicam_log_status(struct file *file, void *fh)
>   		 node->fmt.fmt.pix.width, node->fmt.fmt.pix.height);
>   	dev_info(unicam->dev, "V4L2 format:         %08x\n",
>   		 node->fmt.fmt.pix.pixelformat);
> +
> +	if (!pm_runtime_get_if_in_use(unicam->dev))
> +		return 0;
> +

pm_runtime_get_if_in_use() returns 1 and increments the usage counter is 
active and in use.

I think we need to add:
pm_runtime_put(unicam->dev);

Just before the return 0;

BTW, we may miss a dev_info explaining why the live data is skipped when 
the device is suspended ?

Thanks,
JM

>   	reg = unicam_reg_read(unicam, UNICAM_IPIPE);
>   	dev_info(unicam->dev, "Unpacking/packing:   %u / %u\n",
>   		 unicam_get_field(reg, UNICAM_PUM_MASK),
>
> ---
> base-commit: e98d21c170b01ddef366f023bbfcf6b31509fa83
> change-id: 20260521-bcmpipm-6c578e73239c
>
> Best regards,
> --
> Eugen Hristev <ehristev@xxxxxxxxxx>