--- Doug Ledford <dledford@xxxxxxxxxx> wrote:
> On Sat, 2006-10-14 at 18:21 -0700, Luben Tuikov wrote:
> > > As i found this code was commented out in original driver by Luben
> > > Tuikov with following comment:
> > >
> > > /* Early (current?) SuperMicro mainboards, X6DHR-3G2 and X6DH3-G2
> > > have a bug whereby RS104 is missing (not installed) and RS103
> > > is installed, causing FLASHEX to be 0. */
> > > /* if (!(reg & FLASHEX)) { */
> > > /* ASD_DPRINTK("flash doesn't exist\n"); */
> > > /* return -ENOENT; */
> > > /* } */
> > >
> > > May be it is possible to write separate code for checking
> > > availability of flash chip especially for supermicro
> > > motherboards, but i don't know hot it possible and don't know what is
> > > RS104, RS103 and difference between it.
> >
> > RSxyz stands for "resistor xyz" in the schematic diagrams.
> > This is a hardware bug in the (early?) SuperMicro mainboards.
> > It dates from last year, 20 October 2005.
>
> This wouldn't be the first (or last I'm sure) time a hardware
> manufacturer didn't properly set up the external resistors that signal
> to the chip whether or not certain options are installed. In the past
> I've done searches of the PCI device space looking for specific
> northbridge/southbridge pairs so I would know when to ignore certain
> hardware indicators based upon buggy motherboard setups.
That's a very neat trick! (to identifying mainboards)
Luben
P.S. For aic94xx, all boards shipped out (to customers) do have
a flash chip installed (to store things like SAS phy parameters,
SAS addresses, etc), so it would be safe to ignore FLASHEX bit.
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