Re: [PATCH] sfp: allow cotsworks modules

[Joe Perches <joe@perches.com>]

On Wed, 2018-03-28 at 17:51 +0100, Russell King - ARM Linux wrote:
> On Wed, Mar 28, 2018 at 09:19:01AM -0700, Joe Perches wrote:
> > On Wed, 2018-03-28 at 11:41 +0100, Russell King - ARM Linux wrote:
> > > On Wed, Mar 28, 2018 at 03:33:57AM -0700, Joe Perches wrote:
> > > > On Wed, 2018-03-28 at 11:18 +0100, Russell King wrote:
> > > > > Cotsworks modules fail the checksums - it appears that Cotsworks
> > > > > reprograms the EEPROM at the end of production with the final product
> > > > > information (serial, date code, and exact part number for module
> > > > > options) and fails to update the checksum.
> > > > 
> > > > trivia:
> > > > 
> > > > > diff --git a/drivers/net/phy/sfp.c b/drivers/net/phy/sfp.c
> > > > 
> > > > []
> > > > > @@ -574,23 +575,43 @@ static int sfp_sm_mod_probe(struct sfp *sfp)
> > > > 
> > > > []
> > > > > +		if (cotsworks) {
> > > > > +			dev_warn(sfp->dev,
> > > > > +				 "EEPROM base structure checksum failure (0x%02x != 0x%02x)\n",
> > > > > +				 check, id.base.cc_base);
> > > > > +		} else {
> > > > > +			dev_err(sfp->dev,
> > > > > +				"EEPROM base structure checksum failure: 0x%02x != 0x%02x\n",
> > > > 
> > > > It'd be better to move this above the if and
> > > > use only a single format string instead of
> > > > using 2 slightly different formats.
> > > 
> > > No.  I think you've missed the fact that one is a _warning_ the other is
> > > an _error_ and they are emitted at the appropriate severity.  It's not
> > > just that the format strings are slightly different.
> > 
> > Right.  Still nicer to use the same formats.
> 
> I'll stick a "Warning:" and "Error:" tag before them if you really
> want the rest of the message to be identically formatted - otherwise,
> when seeing reports from people's dmesg, there will be nothing to
> indicate which message was printed.

Not necessary.  It was just a trivial size saving
from the format deduplication.

There is another dmesg info line

	dev_info(sfp->dev, "module %.*s %.*s rev %.*s sn %.*s dc %.*s\n",
		 (int)sizeof(id.base.vendor_name), id.base.vendor_name,
		 (int)sizeof(id.base.vendor_pn), id.base.vendor_pn,
		 (int)sizeof(id.base.vendor_rev), id.base.vendor_rev,
		 (int)sizeof(id.ext.vendor_sn), id.ext.vendor_sn,
		 (int)sizeof(id.ext.datecode), id.ext.datecode);

the next line later which shows that it's a "COTSWORKS       ".