lm_sensors2/prog/detect sensors-detect

[khali@linux-fr.org (Jean Delvare)]

> the point is that we tell people what's at 0x30, that it's associated
> with what's at 0x50.

If we follow my idea to use reads instead of quick writes for the
0x30-0x37 range, then the user doesn't see 0x30 as holding a device, so
we don't have to tell him what's there.

> I went through the datasheets of the Microchip and ST parts pretty
> carefully yesterday, it's clear that it's a byte-write-data that
> does the write-protect.

And other chips (Fairchild NM34W02) say "byte write". If that's "byte
write" in the SMBus way, then it's a 2-byte command (as opposed to
3-byte byte-write-data). I wouldn't swear that we will never see a chip
for which a quick write would be sufficent.

My point is that I don't see the benefit in telling the user that he has
a write-protectable EEPROM, while I see the potential danger in
quick-writing the eeprom's write-protect address.

I would suggest that we comment out the eeprom with $chip = 2 in
@chips_id by default. We can leave it in if some people happen to need
it, but not do it by default.

BTW, at least one EEPROM model (Catalyst CAT34RC02) can also read byte
from its write-protection address, so your detection method would miss
it.

> Clearly the Vaio detection in eeprom_detect() was being called
> both for chip=0 and chip=1, so I changed it so it was only called
> for chip=1. I didn't realize that you did it for both to
> reduce "noise". IMO not doing things twice is better than
> reducing "noise".

Granted. The global detection scheme is poor but making detection
functions more complex to compensate that isn't the right thing to do, I
admit. I think that my main reason for doing that was because
sensors-detect used to suggest bogus module options in that case. Then I
fixed that but did not revert the detect_eeprom function.

> Perhaps a better long-term solution is to call a detection
> routine once and allow it to return different names,
> rather than calling it multiple times, one for each chip name.

Yes, I think that would be the correct way. But this means much work...

- 
Jean Delvare
http://www.ensicaen.ismra.fr/~delvare/