Re: [PATCH 15/16] media: ti-vpe: cal: improve wait for stop-state

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

Hi Tomi,

Thank you for the patch.

On Fri, Mar 13, 2020 at 01:41:20PM +0200, Tomi Valkeinen wrote:
> Sometimes waiting for stop-state timeouts. Testing shows that sometimes
> we need to wait more than what the current code does. It is not clear
> how long this wait can be, but it is based on how quickly the sensor
> provides a valid clock, and how quickly CAL syncs to it.
> 
> Change the code to make it more obvious how long we'll wait, and set a
> wider range for usleep_range. Increase the timeout to 750ms.
> 
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
> ---
>  drivers/media/platform/ti-vpe/cal.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/media/platform/ti-vpe/cal.c b/drivers/media/platform/ti-vpe/cal.c
> index 929f9b3ca4f9..df5a4281838b 100644
> --- a/drivers/media/platform/ti-vpe/cal.c
> +++ b/drivers/media/platform/ti-vpe/cal.c
> @@ -849,19 +849,19 @@ static void csi2_wait_complexio_reset(struct cal_ctx *ctx)
>  
>  static void csi2_wait_stop_state(struct cal_ctx *ctx)
>  {
> -	int i;
> +	unsigned long timeout;
>  
> -	for (i = 0; i < 10; i++) {
> +	timeout = jiffies + msecs_to_jiffies(750);
> +	while (time_before(jiffies, timeout)) {
>  		if (reg_read_field(ctx->dev,
>  				   CAL_CSI2_TIMING(ctx->csi2_port),
>  				   CAL_CSI2_TIMING_FORCE_RX_MODE_IO1_MASK) == 0)
>  			break;
> -		usleep_range(1000, 1100);
> +		usleep_range(500, 5000);
>  	}

Same here, readx_poll_timeout() ?

> -	ctx_dbg(3, ctx, "CAL_CSI2_TIMING(%d) = 0x%08x Stop State Reached %s\n",
> +	ctx_dbg(3, ctx, "CAL_CSI2_TIMING(%d) = 0x%08x Stop State Reached\n",
>  		ctx->csi2_port,
> -		reg_read(ctx->dev, CAL_CSI2_TIMING(ctx->csi2_port)),
> -		(i >= 10) ? "(timeout)" : "");
> +		reg_read(ctx->dev, CAL_CSI2_TIMING(ctx->csi2_port)));

That's not correct anymore, if the condition is false then the stop
state hasn't been reached.

Is this debug statement really useful ?

>  
>  	if (reg_read_field(ctx->dev, CAL_CSI2_TIMING(ctx->csi2_port),
>  			   CAL_CSI2_TIMING_FORCE_RX_MODE_IO1_MASK) != 0)

-- 
Regards,

Laurent Pinchart