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

[maxime.ripard@free-electrons.com (Maxime Ripard)]

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.

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 801 bytes
Desc: not available
URL: <http://lists.infradead.org/pipermail/linux-arm-kernel/attachments/20170306/f0cd5a6a/attachment-0001.sig>