[PATCH 2/3] i2c/pxa: only define 'blue_murder'-function if DEBUG is #defined

[Russell King - ARM Linux]

On Sun, Apr 18, 2010 at 03:22:51PM +0200, Wolfram Sang wrote:
> 
> Sorry to bump this old thread, it dropped off my todo-list :(
> 
> On Sun, Feb 28, 2010 at 03:55:02PM +0000, Russell King - ARM Linux wrote:
> > On Wed, Feb 24, 2010 at 12:01:45PM +0100, Uwe Kleine-König wrote:
> > > From: Wolfram Sang <w.sang at pengutronix.de>
> > > 
> > > This talkative function is also called on timeouts. As timeouts can
> > > happen on regular writes to EEPROMs (no error case), this creates false
> > > positives.  Giving lots of details is interesting only for developers
> > > anyhow, so just use the function if DEBUG is #defined.
> > 
> > Are you sure this is safe?  If you time out the write before it completes,
> > how do you know if the write was successful?
> > 
> > I don't think this is "no error code" nor "false positive".  If the timeout
> > is too short for your EEPROMs, then the timeout needs to be increased.
> 
> I am sure this is safe because we have retries. The eeprom driver first tries
> to write data without a delay, because EEPROMs often have buffers. Once the
> buffers are full, the chip will not answer to the next write request which will
> result in a timeout for this write request. This is expected, so it will be
> retried after some delay. Something like -EBUSY. Only if another "outer"
> timeout passed after some retries, then we have a problem and this should be
> user visible. But the timeout for the write request is nothing exceptional and
> the user doesn't need to be informed about it, especially not in this detail.
> This is what the patch is addressing.

And what if it's not an EEPROM that you're talking to?