[lm-sensors] Adding ICH6 support to the i2c-i801 module,

[lm-sensors] Adding ICH6 support to the i2c-i801 module,

[Craig Sylla]

Hi -

I have a system with an ICH6M chipset (915GM) which has to run kernel
2.6.5.  There are a couple devices on the SMBus which I would like to
get to, an LM63 and a TC655 (fan controller).

The i2c-i801 module supports this in 2.6.7, so I back-ported the
changes (basically the PCI Id) and sensors-detect now finds the bus. 
Here is the output of i2cdetect:

  Installed I2C busses:
    i2c-1       unknown         SMBus I801 adapter at 0400            
 Algorithm unavailable
    i2c-0       dummy           ISA main adapter                      
 ISA bus algorithm

I have 2 questions/issues -

First, is the 'unknown' and 'Algorithm unavailable' normal, or did I
miss something in my backport?

Second, if I try to access any of the devices on the SMBus, I will
quickly get a collision/buslock.  I did not change the i2c_delay()
code to match the msleep() in the backport, could this be affecting
it?  The bus does scan, and I see devices where I'd expect them, so
it's -really- close to working...

Thanks for your help.
Craig

[lm-sensors] Adding ICH6 support to the i2c-i801 module, kernel

[Jean Delvare]

Hi Craig,

> I have a system with an ICH6M chipset (915GM) which has to run kernel
> 2.6.5.  There are a couple devices on the SMBus which I would like to
> get to, an LM63 and a TC655 (fan controller).

Not to disappoint you, but LM63 supports was added much later, in
2.6.10. And I don't think there is a driver for the TC655.

> The i2c-i801 module supports this in 2.6.7, so I back-ported the
> changes (basically the PCI Id) and sensors-detect now finds the bus. 
> Here is the output of i2cdetect:
> 
>   Installed I2C busses:
>     i2c-1       unknown         SMBus I801 adapter at 0400            
>  Algorithm unavailable
>     i2c-0       dummy           ISA main adapter                      
>  ISA bus algorithm
> 
> I have 2 questions/issues -
> 
> First, is the 'unknown' and 'Algorithm unavailable' normal, or did I
> miss something in my backport?

It's normal, the 2.6 kernel exports less information than the 2.4 kernel
did, so user-space utilities can't report the missing information. I
plan to modify the user-space utilities to stop displaying the
information (or lack thereof), so as to not confuse the user.

> Second, if I try to access any of the devices on the SMBus, I will
> quickly get a collision/buslock.  I did not change the i2c_delay()
> code to match the msleep() in the backport, could this be affecting
> it?  The bus does scan, and I see devices where I'd expect them, so
> it's -really- close to working...

Most probably unrelated.

Asus board?

If some device on the bus misbehaves, there's not much you can do,
unfortunately, unless you can get control over this device. This would
require a full knowledge of the bus topology, which manufacturers
usually don't disclose easily.

-- 
Jean Delvare

[lm-sensors] Adding ICH6 support to the i2c-i801 module,

[Craig Sylla]

Thank you for your reply -

On 7/15/05, Jean Delvare <khali@linux-fr.org> wrote:
> Hi Craig,
> 
> > I have a system with an ICH6M chipset (915GM) which has to run kernel
> > 2.6.5.  There are a couple devices on the SMBus which I would like to
> > get to, an LM63 and a TC655 (fan controller).
> 
> Not to disappoint you, but LM63 supports was added much later, in
> 2.6.10. And I don't think there is a driver for the TC655.
> 

Yes - 2.6.10 is right.  I've backported that driver as well.  It
loads, but the bus locks up too fast to tell if it works or not.  I
did the backport by comparing the LM83 from 2.6.5 to 2.6.10, and
applying equivalent changes.
If I can get everything working, I'm hoping to write the TC655 driver
as part of this.  It's a pretty simple device, so basic support
doesn't seem to be an incredibly difficult task.  I've done SMBus
stuff for DIMM SPD's before.

> > The i2c-i801 module supports this in 2.6.7, so I back-ported the
> > changes (basically the PCI Id) and sensors-detect now finds the bus.
> > Here is the output of i2cdetect:
> >
> >   Installed I2C busses:
> >     i2c-1       unknown         SMBus I801 adapter at 0400
> >  Algorithm unavailable
> >     i2c-0       dummy           ISA main adapter
> >  ISA bus algorithm
> >
> > I have 2 questions/issues -
> >
> > First, is the 'unknown' and 'Algorithm unavailable' normal, or did I
> > miss something in my backport?
> 
> It's normal, the 2.6 kernel exports less information than the 2.4 kernel
> did, so user-space utilities can't report the missing information. I
> plan to modify the user-space utilities to stop displaying the
> information (or lack thereof), so as to not confuse the user.
> 

Ok that makes sense - thanks.

> > Second, if I try to access any of the devices on the SMBus, I will
> > quickly get a collision/buslock.  I did not change the i2c_delay()
> > code to match the msleep() in the backport, could this be affecting
> > it?  The bus does scan, and I see devices where I'd expect them, so
> > it's -really- close to working...
> 
> Most probably unrelated.
> 
> Asus board?
> 
> If some device on the bus misbehaves, there's not much you can do,
> unfortunately, unless you can get control over this device. This would
> require a full knowledge of the bus topology, which manufacturers
> usually don't disclose easily.
> 
> --
> Jean Delvare
> 

Ok - I'll need to track down more info.  The board is a specialized
industrial module, so I can probably get details on the bus layout. 
There are a half-dozen or so devices on the bus I'll have to track
down as well to see who's causing the trouble.

Thanks again for your help.

Craig