Re: [PATCH] mmc: dw_mmc: Don't print data errors

From: Doug Anderson
Date: Wed Apr 23 2014 - 12:43:37 EST


Seungwon / Ulf,

On Wed, Apr 23, 2014 at 1:17 AM, Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote:
> On 23 April 2014 01:51, Doug Anderson <dianders@xxxxxxxxxxxx> wrote:
>> Data errors are completely expected during tuning. Printing them out
>> is confusing people looking at the kernel logs. They see things like:
>>
>> [ 3.613296] dwmmc_exynos 12200000.dwmmc0: data error, status 0x00000088
>>
>> ...and they think something is wrong with their hardware.
>>
>> Remove the printouts. We'll leave it up to a higher level to report
>> about errors.
>>
>> Signed-off-by: Doug Anderson <dianders@xxxxxxxxxxxx>
>> ---
>> drivers/mmc/host/dw_mmc.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
>> index cced599..4c8d423 100644
>> --- a/drivers/mmc/host/dw_mmc.c
>> +++ b/drivers/mmc/host/dw_mmc.c
>> @@ -1248,7 +1248,7 @@ static int dw_mci_data_complete(struct dw_mci *host, struct mmc_data *data)
>> data->error = -EIO;
>> }
>>
>> - dev_err(host->dev, "data error, status 0x%08x\n", status);
>> + dev_dbg(host->dev, "data error, status 0x%08x\n", status);
>>
>
> The "status" here could be useful information about the status
> register, which is not considered while printing errors by the "higher
> levels". An option could be to print the error, but not when you
> perform tuning.
>
> No big deal though, just a thought.

Right, I could potentially put the driver into "tuning" mode and then
suppress the errors during that time. If you request it I will do
that.

I will also note that there are many other error conditions in the
driver that don't have such printouts. I think the general philosophy
of this driver is not to print them...

-Doug
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