Re: [PATCH v2 3/8] i2c: bcm2835: Use ratelimited logging on transfer errors

[Noralf TrÃnnes]

Den 27.09.2016 15:01, skrev Martin Sperl:
> > On 27 Sep 2016, at 13:57, Noralf TrÃnnes <noralf@xxxxxxxxxxx> wrote:
> >
> > Writing to an AT24C32 generates on average 2x i2c transfer errors per
> > 32-byte page write. Which amounts to a lot for a 4k write. This is due
> > to the fact that the chip doesn't respond during it's internal write
> > cycle when the at24 driver tries and retries the next write.
> > Reduce this flooding of the log by using dev_err_ratelimited().
> >
> > Signed-off-by: Noralf TrÃnnes <noralf@xxxxxxxxxxx>
> > Reviewed-by: Eric Anholt <eric@xxxxxxxxxx>
> > ---
> > drivers/i2c/busses/i2c-bcm2835.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/i2c/busses/i2c-bcm2835.c b/drivers/i2c/busses/i2c-bcm2835.c
> > index df036ed..370a322 100644
> > --- a/drivers/i2c/busses/i2c-bcm2835.c
> > +++ b/drivers/i2c/busses/i2c-bcm2835.c
> > @@ -207,7 +207,8 @@ static int bcm2835_i2c_xfer_msg(struct bcm2835_i2c_dev *i2c_dev,
> >         (msg->flags & I2C_M_IGNORE_NAK))
> >         return 0;
> >
> > -    dev_err(i2c_dev->dev, "i2c transfer failed: %x\n", i2c_dev->msg_err);
> > +    dev_err_ratelimited(i2c_dev->dev, "i2c transfer failed: %x\n",
> > +                i2c_dev->msg_err);
> Do we really need this error message at all?
>
> Maybe just remove it instead, because error messages during
> "normal"/successfull operations of at24 seems  strange.
>
> Or make it a debug message instead.

I have looked through 64 i2c bus drivers, 8 use dev_err and 2 use dev_warn
on transfer errors (not timeouts). Several use dev_dbg.

I'll change it to dev_dbg instead. Thanks.

Noralf.