Re: [PATCH] mmc: dw_mmc: Change signal voltage error to dev_dbg()

From: Alim Akhtar
Date: Tue Oct 14 2014 - 16:04:46 EST

Hi Doug,

On Tue, Oct 14, 2014 at 9:57 PM, Doug Anderson <dianders@xxxxxxxxxxxx> wrote:
> Alim,
> On Tue, Oct 14, 2014 at 5:02 AM, Alim Akhtar <alim.akhtar@xxxxxxxxx> wrote:
>>> --- a/drivers/mmc/host/dw_mmc.c
>>> +++ b/drivers/mmc/host/dw_mmc.c
>>> @@ -1075,7 +1075,7 @@ static int dw_mci_switch_voltage(struct mmc_host *mmc, struct mmc_ios *ios)
>>> ret = regulator_set_voltage(mmc->supply.vqmmc, min_uv, max_uv);
>>> if (ret) {
>>> - dev_err(&mmc->class_dev,
>>> + dev_dbg(&mmc->class_dev,
>>> "Regulator set error %d: %d - %d\n",
>>> ret, min_uv, max_uv);
>>> return ret;
>> Well, I am ok with this but this info is very useful, what if PMIC
>> failed to actually set the voltage? may be because of some PMIC driver
>> bug or i2c driver bug? Ofcourse this can be found by turning MMC_DEBUG
>> ON, but is that worth in this case. Or is there a way to print that,
>> this failure is because of a regulator re-try?
>> your thoughts?
> I think that the regulator framework and the i2c framework are
> supposed to be reliable. If they aren't reliable there will be lots
> of places that will have problems. I think that you _could_:
> * In your regulator driver print an error when an i2c transfer fails.
> * In your regulator driver print an error if some unexpected event
> happens (like a regulator reports that the voltage didn't actually
> change).
> That would get you want you want, right? ...but an error here doesn't
> belong and that's pretty much determined by (28f92b5 mmc: core: Try
> other signal levels during power up). That patch wants to be able to
> try several different voltage levels and if we print an error in that
> case then it's going to be very confusing to the user.
Hmm...Ok, convincing enough to me, so
Reviewed-by: Alim Akhtar <alim.akhtar@xxxxxxxxxxx>
> -Doug

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