Re: [PATCH 11/16] media: ti-vpe: cal: program number of lines properly

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

On Fri, Mar 13, 2020 at 01:41:16PM +0200, Tomi Valkeinen wrote:
> CAL_CSI2_CTX register has LINES field, which, according to the
> documentation, should be programmed to the number of lines transmitted
> by the camera. If the number of lines is unknown, it can be set to 0.
> The driver sets the field to 0 for some reason, even if we know the
> number of lines.
> 
> This patch sets the number of lines properly, which will allow the HW to
> discard extra lines (if the sensor would send such for some reason),
> and, according to documentation: "This leads to regular video timings
> and avoids potential artifacts".

And possibly buffer overflows !

> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> ---
>  drivers/media/platform/ti-vpe/cal.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/media/platform/ti-vpe/cal.c b/drivers/media/platform/ti-vpe/cal.c
> index b5fd90a1ec09..832f37ebad0d 100644
> --- a/drivers/media/platform/ti-vpe/cal.c
> +++ b/drivers/media/platform/ti-vpe/cal.c
> @@ -961,8 +961,7 @@ static void csi2_ctx_config(struct cal_ctx *ctx)
>  	set_field(&val, 0x1, CAL_CSI2_CTX_DT_MASK);
>  	/* Virtual Channel from the CSI2 sensor usually 0! */
>  	set_field(&val, ctx->virtual_channel, CAL_CSI2_CTX_VC_MASK);
> -	/* NUM_LINES_PER_FRAME => 0 means auto detect */
> -	set_field(&val, 0, CAL_CSI2_CTX_LINES_MASK);
> +	set_field(&val, ctx->v_fmt.fmt.pix.height, CAL_CSI2_CTX_LINES_MASK);
>  	set_field(&val, CAL_CSI2_CTX_ATT_PIX, CAL_CSI2_CTX_ATT_MASK);
>  	set_field(&val, CAL_CSI2_CTX_PACK_MODE_LINE,
>  		  CAL_CSI2_CTX_PACK_MODE_MASK);

-- 
Regards,

Laurent Pinchart