Re: Last old PowerMac G5 that I have access to may be starting to fail: iichb0: I2C error

[Brandon Bergren]

On Fri, Apr 16, 2021, at 11:32 PM, Mark Millard wrote:
> 
> 
> On 2021-Apr-16, at 13:41, Brandon Bergren <bdragon at FreeBSD.org> wrote:
> 
> > Do you have a dmesg? There's some bits in the thermal drivers I've been looking into recently where I have certain machines where the thermal chip is left in automatic mode but also the system attempts to drive it in manual mode, which causes things like the fans jerking on and off and spurious 103.0C readings on the temperature probe the chip is internally sampling. I half wonder if there's a similar issue causing us to accidentally crash the chip or something.
> 
> I'm unclear on what you are after. The only time it left
> any evidence behind was the one line that I reported.
> (It was on the console --and in /var/logs/messages after
> power off/power on.) I've never gotten more information
> from it left powered on, not even via FireWire dcons:
> no response to the outside world until after power-off
> then power-on.
>

What I'm after is seeing what thermal chip is installed in your machine, and what settings it is reporting at power on time. The ones I've been seeing be problematic are adt7460 which were preconfigured by OF to run in automatic mode, but those are specific to G4 powerbooks.

So I'd like to know what hardware is involved so I can look for similar misconfigurations in the appropriate driver by comparing what we're doing against the chip's datasheet.

Since you're getting an i2c error, my assumption is that we are directly talking to a chip *somewhere* here and I'd like to know what that chip is.

-- 
  Brandon Bergren
  bdragon at FreeBSD.org