netdev - Re: [net 21/27] can: mcp251xfd: mcp251xfd_regmap_crc_read(): increase severity of CRC read error messages

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Date:   Thu, 5 Nov 2020 21:54:17 +0530
From:   Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
To:     Marc Kleine-Budde <mkl@...gutronix.de>
Cc:     netdev@...r.kernel.org, davem@...emloft.net, kuba@...nel.org,
        linux-can@...r.kernel.org, kernel@...gutronix.de,
        Thomas Kopp <thomas.kopp@...rochip.com>
Subject: Re: [net 21/27] can: mcp251xfd: mcp251xfd_regmap_crc_read():
 increase severity of CRC read error messages

Hi Marc,

On Tue, Nov 03, 2020 at 11:06:30PM +0100, Marc Kleine-Budde wrote:
> During debugging it turned out that some people have setups where the SPI
> communication is more prone to CRC errors.
> 
> Increase the severity of both the transfer retry and transfer failure message
> to give users feedback without the need to recompile the driver with debug
> enabled.
> 
> Cc: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
> Cc: Thomas Kopp <thomas.kopp@...rochip.com>
> Link: http://lore.kernel.org/r/20201019190524.1285319-15-mkl@pengutronix.de
> Signed-off-by: Marc Kleine-Budde <mkl@...gutronix.de>
> ---
>  drivers/net/can/spi/mcp251xfd/mcp251xfd-regmap.c | 16 ++++++++--------
>  1 file changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-regmap.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-regmap.c
> index ba25902dd78c..c9ffc5ea2b25 100644
> --- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-regmap.c
> +++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-regmap.c
> @@ -330,17 +330,17 @@ mcp251xfd_regmap_crc_read(void *context,
>  			goto out;
>  		}
>  
> -		netdev_dbg(priv->ndev,
> -			   "CRC read error at address 0x%04x (length=%zd, data=%*ph, CRC=0x%04x) retrying.\n",
> -			   reg, val_len, (int)val_len, buf_rx->data,
> -			   get_unaligned_be16(buf_rx->data + val_len));
> -	}
> -
> -	if (err) {
>  		netdev_info(priv->ndev,
> -			    "CRC read error at address 0x%04x (length=%zd, data=%*ph, CRC=0x%04x).\n",
> +			    "CRC read error at address 0x%04x (length=%zd, data=%*ph, CRC=0x%04x) retrying.\n",
>  			    reg, val_len, (int)val_len, buf_rx->data,
>  			    get_unaligned_be16(buf_rx->data + val_len));

I'm not finding this inner debug log useful. Does the user really care
about the iterations it took to read a register? Just throwing the error
after max try seems better to me.

Thanks,
Mani

> +	}
> +
> +	if (err) {
> +		netdev_err(priv->ndev,
> +			   "CRC read error at address 0x%04x (length=%zd, data=%*ph, CRC=0x%04x).\n",
> +			   reg, val_len, (int)val_len, buf_rx->data,
> +			   get_unaligned_be16(buf_rx->data + val_len));
>  
>  		return err;
>  	}
> -- 
> 2.28.0
>