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

[Icenowy Zheng <icenowy@aosc.xyz>]

06.03.2017, 23:53, "Maxime Ripard" <maxime.ripard@free-electrons.com>:
> On Mon, Mar 06, 2017 at 06:32:41PM +0800, Icenowy Zheng wrote:
>>  06.03.2017, 18:04, "Maxime Ripard" <maxime.ripard@free-electrons.com>:
>>  > 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@aosc.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.
>>
>>  Even if it's reduced to debug, it will still flush dmesg buffers.
>
> No, it will not even be compiled by default.
>
>>  Or make it only visible when "debug" parameter is present in kernel
>>  cmdline?
>
> debug messages are visible in dmesg only if DEBUG is defined, which is
> only happening if CONFIG_MMC_DEBUG is set. This won't affect the
> general case in any way.
>
> And it is output only if loglevel is set higher than 7.

Should I make all error messages debug level or only make "RTO"-only
error to debug level like I currently do?

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

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