Re: [PATCH 13/21] amd64_edac: add f10-and-later methods-p3

Ingo Molnar
2009-04-29T19:54:20Z

* Andrew Morton <akpm@linux-foundation.org> wrote:

> On Wed, 29 Apr 2009 21:23:26 +0200
> Ingo Molnar <mingo@elte.hu> wrote:
>
> > > > > + if (CSFound >= 0) {
> > > > > + *node_id = NodeID;
> > > > > + *channel_select = ChannelSelect;
> > > > > + }
> > > > > + }
> > > > > +
> > > > > + return CSFound;
> > > > > +}
> > > >
> > > > this function is probably too large, and also it uses some weird
> > > > hungarian notation coding style. Please dont do that! It's
> > > > completely unacceptable.
> > >
> > > These identifers (or at least, DctSelBaseOffsetLong, which is the
> > > only one I googled for) come straight out of the AMD "BIOS and
> > > Kernel Developer's Guide".
> > >
> > > Sucky though they are, there's value in making the kernel code
> > > match up with the documentation.
> >
> > I'm generally resisting patches that hungarinize arch/x86/ (and heck
> > there's been many attempts ...) but there's some conflicting advice
> > here. I've Cc:-ed Linus, maybe he has an opinion about this.
> >
> > My gut reaction would be 'hell no'. There's other, structural
> > problems with this code too, and doing some saner naming would
> > mostly be a sed job and would take minimal amount of time. The
> > naming can still be intuitive. The symbols from the documentation
> > can perhaps be mentioned in a couple of comments to establish a
> > mapping.
>
> I think I disagree. For those identifiers which map 1:1 with the
> manufacturer's document, the ugliness involved in exactly copying
> the manufacturer's chosen identifiers is outweighed by the benefit
> of exactly copying the manufacturer's chosen identifiers.
>
> Of course, we don't have to use StinkyIdentifiers anywhere else.
> And the nice thing about that is that when one reads the code and
> comes across a StinkyIdentifier, one immeditely knows that it's an
> AMD-provided thing rather than a Linux-provided thing.
>
> Zillions of StinkyIdentifiers get merged via this logic.

Andrew, for heaven's sake, please review the patchset - as i did.

The thing is, up to 12/21, the patches look like normal Linux
patches. (there's problems with them too, but on a different level)

Then do the StinkyIdentifiers show up, in full force:

+static int f10_match_to_this_node(struct amd64_pvt *pvt, int DramRange,
+ u64 SystemAddr,
+ int *node_id,
+ int *channel_select)
+{
+ int CSFound = -1;
+ int NodeID;
+ int HiRangeSelected;
+ u32 IntlvEn, IntlvSel;
+ u32 DramEn;
+ u32 Ilog;
+ u32 HoleOffset, HoleEn;
+ u32 InputAddr, Temp;
+ u32 DctSelBaseAddr, DctSelIntLvAddr;
+ u32 DctSelHi;
+ u32 ChannelSelect;
+ u64 DramBaseLong, DramLimitLong;
+ u64 DctSelBaseOffsetLong, ChannelAddrLong;

Tell me, how is 'SystemAddr' or 'Temp' or 'Ilog' an AMD document
thing?

I have a much simpler explanation really: someone got really bored
at converting some code written For Another OS, somewhere in the
middle - and started plopping Other OS Code into a Linux driver ...

I dont mind the occasional _constant_ that tells us a hw API detail
in whatever externally dictated style - but this thing stinks
HeadToToe ... ;-)

Ingo