linux-kernel - Re: [PATCH] mmc: sunxi: mask all Response Timeout error messages

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Date:   Mon, 6 Mar 2017 11:04:37 +0100
From:   Maxime Ripard <maxime.ripard@...e-electrons.com>
To:     Icenowy Zheng <icenowy@...c.xyz>
Cc:     Ulf Hansson <ulf.hansson@...aro.org>, Chen-Yu Tsai <wens@...e.org>,
        Hans de Goede <hdegoede@...hat.com>,
        linux-mmc@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mmc: sunxi: mask all Response Timeout error messages

Hi,

On Mon, Mar 06, 2017 at 12:45:35AM +0800, Icenowy Zheng wrote:
> Response Timeout is very usual: it will happen when trying to run some
> commands that do not belong to the card; it will happen when some SDIO
> card transfer beyond its SDIO bandwidth; and when the MMC controller is
> set to poll the card with "broken-cd" property (the Lichee Pi series of
> boards do this), it will flood to the console and make the console
> unusable.
> 
> Mask all response-timeout-only error messages, only show it when another
> error happens.
> 
> Signed-off-by: Icenowy Zheng <icenowy@...c.xyz>
> ---
>  drivers/mmc/host/sunxi-mmc.c | 13 +++++++++----
>  1 file changed, 9 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/mmc/host/sunxi-mmc.c b/drivers/mmc/host/sunxi-mmc.c
> index 6ffcd2838272..7828e1f57cf0 100644
> --- a/drivers/mmc/host/sunxi-mmc.c
> +++ b/drivers/mmc/host/sunxi-mmc.c
> @@ -483,10 +483,15 @@ static void sunxi_mmc_dump_errinfo(struct sunxi_mmc_host *host)
>  	struct mmc_command *cmd = host->mrq->cmd;
>  	struct mmc_data *data = host->mrq->data;
>  
> -	/* For some cmds timeout is normal with sd/mmc cards */
> -	if ((host->int_sum & SDXC_INTERRUPT_ERROR_BIT) ==
> -		SDXC_RESP_TIMEOUT && (cmd->opcode == SD_IO_SEND_OP_COND ||
> -				      cmd->opcode == SD_IO_RW_DIRECT))
> +	/*
> +	 * Reading timeout is usually normal, especially when doing
> +	 * card-polling with "broken-cd" in device tree.
> +	 * If do not mask it, the RTO error message will flood the console
> +	 * and even hide useful error messages.
> +	 *
> +	 * Some SDIO commands will also normally timeout with non-SDIO cards.
> +	 */
> +	if ((host->int_sum & SDXC_INTERRUPT_ERROR_BIT) == SDXC_RESP_TIMEOUT)

We really shouldn't silence legit errors.

The actual problem here is that we log them as error, we could
probably reduce it to debug.

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

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